The ZTE MU5001 seems like an interesting device to support.
- mainly for Europe (US band coverage is weak)
- 150 GBP used, but there’s a large used market so price is going to drop further I hope
- has 5G
- preexisting hacks: https://github.com/ZTETool/ZTE-MU5001-HACK (no root though)
I have no idea if the qualcomm chipset it uses has diag though (it’s not MDM* type device)