My XBOX Series X gets a bit loud when playing on 4K at 120hz. Is this normal?

i'm very likely because it's running at the top end of its abilities the fan would go faster to compensate for the heat being generated

you're running it at the top and that 100%, it's not supposed to be silent just quiet. If you're shoving it in a tiny hole like that, you're interfering with the system cooling which is not helping your issue.

you should always place it in the most open location possible, and I recommend always placing it vertically unlike every other system for max cooling

I changed the position of the XBOX and placed it in an open space and the loud noise of the fan completely disappeared! It was mainly due to the fact that it was located inside the cabinet. Thank you for your help.

Actually, the console is located inside a stereo cabinet similar to the first image. The sound of the console gets higher but does not shut down. Do I need to change its location in this case?

I will do it the way you are recommending and check if it helps solve the problem or at least make the sound lower. Thanks.