To early to tell, we will have to wait for it to be released and benchmarked by Phoronix. But judging based on previous Zen5 CPUs and becnhmarks on GNU/Linux it should be very good. But let’s wait and see and also it will depend on how much it will cost and how much each one is willing to spend.

Depends on the specific distro and their upgrades policies.

Usually with normal distributions you get an update to a new major version (e.g. from Plasma 6.0 to Plasma 6.1, or some versions can be skipped) when a new version of the distribution gets released, and in the mean time you only get bug fix releases (e.g. 6.0.x to 6.0.y). Sometimes some distributions also make special backports available to bring new major versions to same distro version.

With rolling release distributions (e.g. openSUSE Tumbleweed) you get new major releases in a few days after they are released.

So you need to check with Nobara how they handle this.