I have a second server, unraid, with 24TB, 8 of them used, a couple virtual machines, with windows, one is my main computer with gtx graphics pass. Another is a windows with blue iris. Then I have quite a few containers. I am considering migrating to unraid 6.9 now because I use a Ryzen 3950x with x570 board and I cannot monitor the temperatures and I read that in the new version it already works well. What do you think about this update is it very hasty or is it stable enough to migrate?

IF you look at my signature you will see that I  am running 6.9.0-beta29 and I don't have any problems.  However, I don't use any VM's.  In reading the release thread for -beta29, there appears to be some problems with some VM setups.  If you want to make the jump, you should read the thread and make a decision based on your hardware setup.  There have been reported no issues with the 6.9.0 betas for the basic NAS functions so your data will be safe.  Always wait for a few days before jumping on any release (beta, rc, or stable) is always a good policy...