Have you looked at the Intel RTF drone? It looks very nice, and comes with a far more powerful OBC than the solo.
In general I agree, there’s a terrible lack of multicopter hardware to run ardupilot/px4 and is pushing this project more and more into niche territory.
I have one of these which is quite nice - for it’s size has lots of real estate to put things on:
https://www.electricwingman.com/tdrones-smartx-quadcopter-a-artf
You could use something like a pixracer and the upcoming up core OBC, would fit well.
I know this will probably be too DIY for you, but:
https://discuss.ardupilot.org/t/dev-frame-development-part-2/20220