Everspace 2
full 6DoF (like Descent)
More like a looter shooter so there is a lot of fluff one may like or not
Progression is very rigid with many systems locked out by quests and stories
there is a level up system that is also very rigid, if you have, say, level 20 weapons, forget being able to do damage to an enemy that is level 25.
Story is a sprawling thing about saving the galaxy and whatnot.

Rebel Galaxy Outlaw
WWII planes in space gameplay
you can go anywhere anytime, there are only "soft" limits like systems where going with a starter ship and weapons is extremely dangerous.
Some minigames in the stations, like pool and an arcade machine with a clone of Asterois (which will unlock an extra mission if you reach the high score)
fewer ships and weapons but with more pronounced differences
No levelling system, in theory if you are really that good at the game you can take on late game enemies (within reason of course) but there is no rigid "late game enemies cannot be damaged by the starter laser" rule.
Story is a small revenge quest that turns into a space gangster story late on.

RGO in general is also a straight clone of Wing Commander Privateer in basic gameplay and art style (with some improvements here and there, mostly elements of games like Freespace or Tachyon), so in some ways it's more unforgiving than E2 but has a more old school sensitivity.

Thx! Which one do you prefer and why?

I have a softer sport for RGO, I prefer the less rigid progression and I am really nostalgic for 90s "WWII in space" spacesims. It's also a simpler and more contained experience. And I really like the grungy look that tries to emulate the look of the colorful pixel graphics or early Wing Commander games but in 3D.

Everspace 2 is still fun but at times I felt the hard stats RPG system and gated world were a bit stifling, also I'm not quite as fond of full 6DoF combat. And the looter shooter fluff was a bit annoying at times, with all the materials, crafting and just getting tens of the same weapon with only slightly different stats.