At least for rc3 I am aware of bugs with firewall not reloading properly in some instances, which is a proper dealbreaker for any kind of release. (The move from fw3/iptables to fw4/nftables is one of the biggest changes with 22.03.)
You can always look at the 22.03 git shortlog and see what has been fixed between now and the rc2/rc3 tags.
Generally speaking though, a tag, even if it gets compiled and put onto the download server, is not a release. An RC is a test -- and can also be a test for the build system. Always wait for an official announcement, there's a reason they don't happen immediately, and the devs being lazy is decidedly not the reason.