Edit: updating Steamworks common redistributables fixed it. AMS2 and the beta branch are the only ones that do this for me, but it occasionally just decides to get stuck when launching. I've checked the drive, validated files, rebooted, reinstalled GPU drivers, cleared the Steam download cache, and nothing. The only thing that solves it is a full reinstall or manually deleting files and revalidating. No clue what's causing it. Pcars2, which is on the same engine, and even on the same SSD runs perfectly fine. I've checked it with running VR and standard 2D screen and both refuse to load.