Things like stepper motors and driver bricks are commodity items; if you buy from reasonably reputable Amazon / eBay sellers, they’ll work just fine. In this context, “reputable” means specializing in techie hardware and not also selling beach toys, fat-tire e-bikes, and cosmetics.
I have three different laser power supplies sporting three different brand labels with identical ZYE PCBs inside. The one I bought from Cloudray with a Cloudray sticker may be better than the dead one with a ZYE sticker, but to my eye they’re all the same.
Laser tubes seem to be another matter, where buying from a reputable seller, like Cloudray, should get you a fresh, good-quality tube. Buying from J. Random Seller will probably get you a fourth-shift QC reject with a really pretty sticker.
Stipulated: I may be too cynical.