Well, I don't have a Zoom Room to test with, but I've poked around and not found any different restriction for a Zoom Room advance schedule limitation. (Not saying it doesn't exist -- I just haven't found one!)
I did schedule a monthly recurring meeting starting tomorrow and running through July 2026:
The yellow highlights are what I put in; the red underline is what Zoom used to describe the meeting series. No error message on hitting Save.
If your user with the issue could grab a screen shot of the meeting recurrence parameters and any error message received... forward them here and I'll take another look.