All I can say is buying misdescribed 'untested' crap off ebay decades after manufacture and then having problems with it <> Amiga is pure shit.
I've never had Agnus/Denise/Paula fail on any of my OCS/ECS machines bought new and ditto for Lisa/Alice/Denise on my A1200 or A4000 I bought in the 90s. I have had many many graphics cards burn out just because a PC was left switched on for 2 days (just showing the desktop, not actually doing anything) though.
So really I never ever had a problem with any of the machines I bought new, I have had dodgy machines bought off ebay second hand but that's not the machine's fault it is the fault of sellers being twats.
Always suspicious of people selling used computers or cars, they usually sell due to a fault that only they know about to get out of repair costs.