Try a high-end Denon. I like 'em.
I have one I do not use (4308 - over three thousand bucks - bought it when I was still rich-ish). It is quite wimpy, if compared directly to the older Yamaha.
The modern Denons which might possibly be as powerful as what I am used to using cost almost six thousand dollars and I have only sen on their website, not really available locally. To begin to approach what I already have, the cost is closer to twenty thousand bucks.
I will take this one apart and find out why it is thermo-cycling and keep it a while longer.
... increase the ventilation in my cabinet ... etc.