Take it to a qualified tech. He will examine it and clear off any hidden concerns. Don’t get sucked into the costly default position of a brand new power switch etc,
I had a similar instance on my beefy integrated amp. The tech first popped the case , he checked things out with the open unit easily viewable, and then carefully inserted a DIY “spacer” to permit the power button properly release the “jamming” and return to a normal on-off push / push position. Apparently it is not an uncommon issue with pre-owned units that have a tendency to “jam” especially when warm .
The case was put back on and that added “spacer” solved the issue.EZPZ.
FWIW.