This post has been marked by the post author as the answer.
Not sure if this is the issue, but MAX is in Early Access and is updated fairly frequently. Some of these updates introduce new issues. I believe the latest release and the latest experimental release have issues with stand alone games not being able to run. If that's still the case, then that may be your issue. You can always use Steam to roll back to a previous version (2022.08.19 should work for you) until this issue is sorted out.
Intel i9-10900K 5.10GHz, 64 GB RAM, Nvidia GTX 1080 ti 11GB, Windows 10 64-bit, dual monitor display