No there was HPC sku of Windows 2003 and 2008 : https://en.m.wikipedia.org/wiki/Windows_Server_2003#Windows_Compute_Cluster_Server
Microsoft earnestly tried to enter the space with a deployment system, a job scheduler and an MPI implementation. Licenses were quite cheap and they were pushing hard with free consulting and support, but it did not stick.
Traditionally virtual tty 1 through 6 were text terminal. So X used the 7th, that’s why some older forums tells you to go there.
Nowadays, the graphical session manager will spawn on vtty 1, and sessions will dynamically use the others. So on a mostly single user computer, Ctrl+alt+F2 is likely to work. With multiple users, you can actually switch users or come back to the session manager this way.
If you switch to an unused vtty, systemd will spawn a text login prompt. And when you login, some logind dark magic makes the system realize your are entitled to hear the audio output of your application still running on your graphical session.
Valheim uses proton? I’m pretty sure it ran natively a few years back.