AFAIK, they do next to nothing in terms of software support. It tends to come down to the community and the manufacturer of the SoC they use to make this stuff work. They're just getting cheap hardware in the hands of developers and hackers and trying to get people on-board. The RK3399 in the Pinebook Pro is very well-supported by now, though a bit old and low on RAM. I would trust that most RockChip stuff will eventually (maybe 3-5+ years after availability) get good support. The QuartzPro64 should be coming along slowly now, and I imagine once it's better-supported we'll see a Pinebook Pro 2 with the same RK3588. Similar to how we had the RockPro64 before the Pinebook Pro. The PineTab 2 and PineNote base off existing RockChip stuff (RK3566) they're already using in some SBCs (Quartz64), so we should see a lot of their devices improve at the same time.
For the same reason I expect the Orange Pi 3B and 5 Plus to mature with the current latest Pine offerings. As long as you stick to stuff with these popular chips, there's a decent chance the devices will become usable eventually. I would avoid anything too new or obscure when getting ARM devices.
All of these devices are already usable quite well for some purposes. Pretty much the level of support follows how long they were available. But neither is particularly unusable.
