Latest update:

I have been able to verify that this game is extremely sensitive to voltage/frequency tweaks to the GPU and RAM, and likely the CPU —although I have not experienced the latter despite being also tweaked.
In my experience in the case of the GPU the game crashes —as common; however —much less common—, in the case of RAM the game presents persistent and very annoying stuttering.
This, far from being bad, is very good for those of us who have some or all of those components tweaked to its limits, since HZD is a very good stability benchmark —I must say that in the rest of my library both components were apparently stable.

Original:

My experience is with a 5600X, a 3070 and 16GB of RAM with everything maxed out (just without blur) at 1080p and 120 fps locked (to maintain consistency and lock the frametime), so nothing special.

Although the game, considering the above, is not exactly light ―it stresses the CPU and GPU, especially the CPU (and I'm not sure if it's justified or not)― I have no problems with maintaining the framerate, but unfortunately for some reason, that I still don't know, sometimes the game suffers from constant and consistent frame drops, particularly, curiously and unpleasantly from ~5 frames every few seconds, this makes the game extremely irritating.
The first time I experienced that, I did a few things to try to avoid it, such as disabling W10 Game Mode, resetting the CPU and RAM to factory settings from BIOS and resetting the GPU from Afterburner (undoing the stable overclock and undervolt on all three), disabling GeForce Experience, using the game's internal frame limiter, activating the Maximum performance profile for the GPU, and some other things... until after a reboot it worked, the frame drops disappeared. I reset the above to try to detect the problem but I couldn't detect it; fortunately after reestablishing everything above the game continued to work fine. That was yesterday.
Until today, the game again presented the same horrible frame drops, but after several restarts it worked again, without having a clear idea of the cause, again.

When there are no frame drops the game looks and feels wonderful and beautiful, the gameplay and the cutscenes.
Even though on the other hand the horrible and ridiculous pop-up can completely ruins the experience, especially when you advance quickly (I don't want to make a small spoiler) or at certain moments during the day (worse if they are both at the same time). Despite they improved the pop-up regarding the PS4 (I have been able to play that version), it is still terrible on PC.

Although I consider it is a good game so far, both things have made me consider a refund because both issues completely break the experience and immersion and speak about a deep carelessness from Guerrilla (or whoever is in charge) and Sony with their product and with their clients, since both are topics that have been known for a long time, which is a huge shame.
I really hope that the frame drops don't happen again, but as for the pop-up, unfortunately everything seems to indicate that there is nothing to do. We will see.

Yesterday, a day after posting this, I had a session of several hours and fortunately the frame drops no longer occurred and, as I said, the game is beautiful at a stable 120 fps.

However, in "the second part" of the game I had two crashes (I hadn't had any) I checked in the Event Viewer and both were related to the graphics card ―strange thing because in all the other games my oc and uv are stable―, so I decided to try another auto oc setting in Afterburner; that configuration is apparently "more extreme" in the game since the GPU reaches very high frequencies when its use is not high with a voltage that I have not verified but that seems unfeasible in terms of stability, but strangely after 5 hours of gaming it didn't give a single crash. So confusing.

Be that as it may and despite its flaws, I must say that the game manages to keep you in it.

So since I've already played some hours and there have been ups and downs, I think it doesn't seem honest to ask for a refund now.

Which version of Windows are you running? Since updating Win11 to 23H2 it doesn't even start for me anymore (it did before on Win11, and I was able to replicate this behavior on multiple PCs)

I'm on W10 22H2.

After having one more crash after some minutes within my next session, I discovered that the reason for the crashes, as the Event viewer suggested everytime when that happened, was my manual uv and oc, they were not completely stable ―despite being stable in the rest of my game library―, so I have increased the voltage one step more (~6 mV) and it's been around 10 hours in the game and I haven't had a single crash anymore. HZD has turned out to be a good stability test for the graphics card.