I think you’ll find some ISPs will be reluctant to let go of CGNAT - they’re doing quite nicely by charging extra for ‘commercial’ services where it’s not in the way.
Fortunately, many of us know about cloudflare tunnelling and other services, so NAT really isn’t a problem to self hosters and even SMEs any more.
A non technical answer: Don’t interact with other players and don’t give out any personal information.
Use a unique and non-memorable username in steam and in game. Don’t use any of the social functions in steam.
It’s often overlooked that the biggest risk to personal information is the person themselves.
(Obviously you need to give some information to Steam for purchasing, and others have shown other methods to limit what information is sold about you as much as you an. It also depends where you reside - the EU has better protections than most)