The first thing to say is that this isn't actually a first person shooter. It sounds so trivial, but shooters have fast gameplay. They're about constant repositioning in a 3D space to reduce the risk of getting shot, while of course also being able to return fire and accurately hit enemies. That is simply not the gameplay model in CP77.
This is an RPG in first person. You do not see many cops bunny-hop around with a lot of 360 spins, and none of the demo footage so far has suggested that kind of fast paced gameplay. There is shooting in the game, and repositioning is a theme, but not at the frantic pace of FPS games.
That aside, motion sickness does happen to me as well, when the camera is moving around too much or in ways that just aren't how my brain thinks it should be moving. Watching pro gamer footage from FPS games is usually not pleasant.
My suggestions, use them if they work, and obviously YMMV.
Reducing your mouse sensitivity can be slightly annoying but it does reduce micro-movement of the camera due to tiny tremors in your hand.
FOV angle, we don't know if it can be adjusted, but maybe. Some people feel like they're boxed in at default and widening the angle gives them a better and less stressful experience.
If there is weapon sway to simulate movement, turn it off.
Fiddle with the graphics settings to get rid of things that flicker. Dynamic shadows, for one, can some times be all over the place and having shadows move around is one thing that can fuck with your head. Also something like grass, while nice, can often end up very visibly switching back and forth between long range "low poly" mode and close range "high res" mode. If I can't get the draw distance far enough away, I prefer turning it off.
Make sure your frame rate is decent and constant and your mouse move is consistent and lag-free. You want the things that happen on screen to be as predictable and closely connected to the commands you're giving. If some eye candy is causing FPS drop in certain situations, switch it off.
Make sure that the brightness and contrast is reasonable to avoid eye strain. Not too bright, not too dark.
Make sure the environment you're playing in is good. Reasonably fresh air, reasonable temperature, decent ambient lighting.
Don't feel bad about taking a break every so often and just spend a minute or two staring at a nice fixed point. You're not moving, the point isn't moving, just breath in and out and regain your balance.