Are thru-axle QR adapters wheel specific or generic?

My 12x100/142 TA wheels came with QR adapters. I am looking for a set of wheels for another bike and can find decent deals on some TA take-offs (Giant) but it doesn’t look they have QR adapters. Are the adapters generic enough between wheel brands to use?

They are pretty much wheel, or rather hub specific.
Try and identify the hub and see if this can help. To give you an idea quite a few OEM wheels actually use rebranded DT Swiss hubs so you should be able to convert to different axle standards.

I kinda of thought that.

The ones I have come from Prime (Chainreaction/Wiggle) wheels and their hubs are RD02 branded.

might be an idea to contact their customer service and ask them?