there are only a few panel makers

samsung and lg are the largest
and they dont even use their own panels in all their displays

iv seen lots of lg tvs/monitors with samsung panels, and samsung tv/monitors with lg panels

look up reviews on rtings to see how they actually perform
https://www.rtings.com/monitor

but even then, there are some variants with different internals than the reviewer receives
exact models can still have differences

Asus has the best, for both QD-OLED and OLEDW.

They do use their own panels, but also the competitors because there are trade offs and cost differences. And supply.