10 seconds of googling?
Also, since I am here, when I worked as a CTO, I got some briefing on what makes information "personal" for the purposes of GDPR. It's a nightmare due to a vague clause that says "can be reasonably attributed to a natural person".
So IP address - personal?
Case (1) - IP is from a company that does not log user access. Does not resolve to a natural person. No.
Case (2) - IP is from a home address with a single person and country allows private citizens/corporations to subpoena ISP records. Yes.
Case (3) - IP is to a share house with open WiFI. Who knows?
So - a company logs IP addresses, is this PII? Shut up and sign off on your compliance....
So SteamIDs? Also grey areas. Will Steam give Epic enough information to identify it to a natural person? Maybe if sued - in your jurisdiction? In the US? In Europe? I doubt anyone could say, and even if you were a judge, subject to appeal to a higher court and then eventually a parliament.
Maybe stop worrying about it unless you have millions for an international court case to test.