Turing RK1 and similar, nVidia not as much given their platform accessibility is barely better than Broadcom. RK1 is not particularly great either but significantly better than either Broadcom or nVidia.

I agree the really well supported platforms are both older as well as more expensive (e.g. i.MX & Sitara platforms.) However, I won't call the RK1 "expensive" considering it outperforms the Raspberry Pi (5) by a larger factor than it is pricier by (roughly.)

[Ed.:] Actually, no, the RK1 isn't better either, given there doesn't even seem to be a datasheet available for the module as a whole.

I guess I'm just living in my expensive but well-supported world of NXP, TI and ST SoMs that I can actually debug…