I have already played it some tenths of hours. I am aware of the multiplayer and other little lies about true freedom of flight, other than that it is NOT a true PC game but just a PS4 game porting... ...But right now I am starting to suspect that also the survival and exploration genres are fakes, instead I am going to think this game is just an arcade/casual game.

I am unable to do any backtrack on already discovered bases on already discovered planets. I mean: if I leave a planet after I have explored it a bit then I save the game, in the space station for example, then I quit, when I load back the game I am unable to visit again an already discovered base on an already discovered planet.

I have some suspects that everytime you leave a planet the planet is totally forgotten, and if you go back on it is generated again, the only things it holds are the name, the biome, animal species and plant species that live on it... ...Worse I have also the suspect that when you go enough far away from your starship on foot exploration, in some way, your starship "follows you" at the nearest landing pad or recall signal to its old position in the cell that is currently generated (in this case if you do not leave the planet also the terrain info is retained)...

These suspects remind me the Savitch's Theorem...

...Do you have also these suspects? What do you think about?

Well of course it's a survival/exploration game. I'm not entirely sure what does the 'fake' bit mean since it actually is a survival/exploration game. It's just an extremely technically inept survival/exploration game which needs like 5 more years in development to even sort out these issues, let alone implement stuff like multiplayer or improve planet generation into something which would handle advanced stuff like ... Idunno ... Rivers or large mountain ranges. That even Minecraft can generate. ... *sigh*

You are correct in that if you leave a planet to go to another or the space station, all changes made to that planet except saved discoveries are reset. All mined items restored. All collected resources restored.

Yes, when you leave a planet it is forgotten and then when you revisit it it is procedurally regenerated from its "seed". This information hasn't been deliberately hidden from people, it's the way the procedural generation of the universe in the game works.

When you leave a planet that has been discovered by you, and when you (once in space) point to this planet again, it will be remarked as "already covered" or some such.
If you additionally named this planet, the initial name will be changed into this.

OK, as long as you stay within this system of planets, the name will stay.

What happens if you warp to another system ??

HG said that you can return to any planet, but HG already said way too much - so to maybe test this out you will have to get to (and name) two galaxies.
If the whole thing is not a Voxel fake, you might get lucky and - by naming stuff - map out a snippet of NMS.

According to HG the planets you have seen will remain as they had been when you left them.

My thoughts - at first start of the game you will be given one planet, either from scratch or as the result of a save.
You also will get the visual representation of this large universe. The names and numbers of it generated during start up.

OK, when you leave "your" planet and go into warp to a new galaxy, this new galaxy will be generated while you stare at the representation of the warp in action.
So during your stay in NMS you will always be in one Galaxy that had been created during a loading screen.
The rest of the universe - simply a product of your grey matter and listening to HG.

If I am unable to do any backtrack because everything I have discovered on a planet surface is permanently overwritten by the new procedurally generated content than it is not an exploration game, because everything is uncharted again...

...What kind of exploration is it when everything you have discovered is lost? Having no map of any discoveries everything is uncharted remains uncharted, I really think that this is NOT exploration...

...About survival is a more complicated matter to argue, let me explain in this way: in this game you can build nothing other than what you are able to keep with you, what kind of survival is it if you can not build any sort of base/refuge?

I am very sorry if I am really educated in wrong ways by games like Subnautica, that is a survival/exploration game, maybe far away from perfection, but a true survival/exploration game.

Maybe it helps when you think of NMS as a chunk of rooms, many rooms.
The doors between these rooms >>> warps >>> loading screens.

Basically you always be in one room because there only IS this one room. You can take things with you from one room into another, but that's all about it.

HG simply told not the truth when they said " ... no loading screens!"
There is the warp (loading screen), and there is the thruster (loading screen). One for galaxy travel, the other for planet travel.

So, no matter what HG tries to tell you about size: NMS is incredibly small (ever wondered about the install size?)!

In a computer science way, this piece of software can be used as a Savitch's Theorem proof, that is, it is wonderful...

...But in gaming way it is no more than a consolle arcade/casual game.... (...and as far as it runs round and smooth, for the first 30 hours, it could be really addicting...)

When you visit a planet, it generates terrain based on a random number, but it's the same random number each time you visit that planet, so the geography it creates will be the same every time. If the game had a better navigation system, you'd be able to easily find places you'd already been.

If it should be so, also the terrain is retained, but about everything is standing on planet surface and caverns?

I know what it is a pseudo-random number and I know that if you have the initial seed you could (re)generate all the sequence of pseudo-random numbers...

I'm pretty sure that any deformations and used resources stay the same, at least if you stay in the same system - I haven't tried backtracking to a previous system to check if it resets then, but all the stuff I've mined or collected has stayed mined or collected when jaunting back and forth between the planet and the space station.

Now, I do believe that if anyone ELSE came to the same planet, it would still be pristine for them (apart from the name/recorded discoveries).

So you were able to do backtrack on a planet when you left it for the void of space...

...How have you done it without any sort of map or beacon or any other sort of reference?

I discovered a whole bunch of beacons in the same general location before taking off - coming back to the planet I just sighted on one of them. Beacons seem to always locate the nearest trading post whether you've discovered it before or not, so activating it pointed the way back to a place I'd already discovered. It's not exactly the most efficient wayfinding method out there. I really wish the game would just give you a list of your discovered waypoints and allow you to designate any one of them as your current destination.

Ok it is interesting, but it seems to me, but maybe I am wrong, that the beacons are disposable, I mean I am able to use it only one time. Ok you have discovered a lot of them that you think have pointed you to the same base, so everytime you land you use another one...

...If it is so, and they are disposable, when you have used all of them, what have you in mind to do? More, if the location has not so many beacons that points all to the same trading post, what have you in mind to do?

I was pretty sure I've seen my own mining leftovers when returning to the planet. You can see the markers (ruins, trading posts etc) from space which is how I know where I was and where to return to.