Easy answer for ya: commercial electronic equipment should not exceed 70C operating temperature, per IEC 61010 (likely also in UL code).
This is why Bambu cuts it off at 65C.
You may be able to operate beyond 70C by a few degrees, but don’t be surprised if you run into a few issues, mechanically or electrically. 75C would be as far as I’d push it…
In case it doesn’t go without saying: operating the machine above 70C is voided warranty territory IMO.