I had big problems getting tyres (with tubes) on my Arch Ex wheels.
The good people here recommended purgatorys by specialized.
I got these on but they wouldn’t seat properly, so this afternoon I left both tyres out in the sun, so that they were nice and warm, and then got the washing up liquid out.
With a bit of careful manipulation I now have 2 properly seated tyres. I thought the rear wasn’t going on properly in a couple of spots so I pumped it up to 40 psi to push the beads out. I nipped indoors for something and the tyre seated itself while I was indoors.
Might be worth a punt with purgatorys, maybe, even if you just buy one for now. £30 gotta be better than new rims.