Software support is so crucial. I can't stress that enough. There is a huge amount of work to prepare the kernel and overlays for a new board and many manufacturers do the bare minimum.

My experience with vendors who do this well are Asus tinkerboard, NVIDIA Jetson (well... I'm being kind there) and from what I've heard the pine products. Basically go to armbian and look for the boards with the most mature support.

I've been working with dozens of these things for the last 4 years and the amount of issues due to poor kernel support saddens me. So much wasted time, they can be amongst the most expensive computers you can buy.