Wait, I used OrangePi's with Allwinner chips before precisely cause of their cheap price and mainline linux support. At the time (~5 years ago) Rpi was worse, foss-wise. Here is a wiki documenting the efforts: https://linux-sunxi.org/Linux_mainlining_effort
What am i missing?
i use orangepi prime boards in production as remote NIDS. i used Armbian (a great debian porting project that does what the maker should have done ) until orange released their Debian 10 img. I put an endurance rated sdcard in those pis and they run like the little pink bunny! Love these little orangepis. I have tried a handful of other boards ( beagle, raspberry, banana , have a whole stack. too many to remember) but the oranges are solid. On a lot of these little SoCs, you can use the raspberry pi gpio software since many of these boards follow the same gpio standard & plug in/out.