That sucks! I don't get any motion sickness, so no personal recommendations, but have you tried some of the common tricks (like increasing FoV, disabling motion blur)?
As someone else said, try turning up FOV. Last night I decided to try Doom Eternal for the first time. (I played the new Doom but didn't finish it.) The default FOV is 90, and motion blur is on. In a game mostly involving corridors and fast movement, 90 is stupidly low. It's set up for people playing on a TV 6+ feet away, not a comouter monitor much closer. These two settings may be your issue.