Cheap parts are OK in certain places, but not in quality hi-fi gear.

Cheap Chinese parts are everywhere and they have a place in very affordable equipment, clock radios, Bluetooth speakers, etc. I’d suggest that a technician advising you that cheap Chinese parts are perfectly OK to use in quality hi-fi gear is probably not someone you want to use.

“But Mike, Musical Fidelity uses cheap Chinese parts!”

Yes, they do, as do many manufacturers including Cambridge Audio, NAD, Redgum and many more.

The single most important reason manufacturers use the cheapest Chinese parts is to save money. Many parts are now manufactured in China but not all of them fall into the super-cheap category. There is no good reason to fill boards with the very cheapest parts, other than to save money. That applies to manufacturers and repairers.