@zero064 Thank you so much for all your inputs, I really appreciate it.
I got a server set up on my second PC with SteamCMD after playing around with settings and reading all the articles, also I watched yome videos for more options. And yes, it works with the "-ServerPlatform=ALL" option which @darkradeon mentioned in his comment, without it, XBOX and Microsoft PC version players are not able to see the servers.
I am now struggeling with performance on the PC. My GPU is a RTX2070S which is not even fully loaded when the game is running, but FPS is dropping very low to 20FPS and lower. Gotta figure that out. Also I have to migrate all my server settings from my ASE server to ASA.
The XBOX version is running fine FPS wise, but it seems like there is some HDR bug. Everything seems to have a overrated RED saturation.
BTW. is there some recommendation on how to properly shut a server down besides just closing the server console? And also is there some sort of GUI for the server console?