With the same SoC, it should be about identical support-wise.
It just launched, give it time. The whole point of VisionFive 2 is precisely to get these boards to developers in large numbers so that it can all be bootstrapped.
It's been a while but nothing from pine64 was well supported without hacky 3rd party custom kernel rolls and the like, with no apparent effort to move stuff into mainline.
Look at the PinePhone, Pinebook Pro, and RockPro64. All have mainline support and you can run several distros on them. I consider them the gold standard in this space, although it's thanks largely to the community and not the actual company. Anything newer than RK3399 will probably take a few years to become very good, but I'm sure mainline support is in the cards so long as the device is popular enough and Pine64 can sell enough. (Their PineCube IP camera device was a failure in recent years)
postmarketOS also does a lot in this space. Their developers often help to improve support for everyone on a board.
I got them all when they came out (trying to help support the concept, even if execution wasn't quite there yet). I haven't used them in a while, because it was such a shitshow. Glad to hear things have gotten better, might need to dig them out of the closet.
It just launched, give it time. The whole point of VisionFive 2 is precisely to get these boards to developers in large numbers so that it can all be bootstrapped.