Can you get these from vendors like Asus and lenovo these days?

The ones I've seen on aliexpress are from unknown Chinese vendors.

I have a Framework Desktop as primary PC (great cooling, beautiful case with handle) and the Bosgame M5 dedicated for AI use.

I was also a bit wary about Bosgame but TBH they've been great and the machine is rock solid, if a little noisier than and not as pretty as the FD. You can just buy from them directly and be fine, best computer deal out there by a mile.