how big is difference between rc1 and final release?
I upgraded all of my systems to Trixie already. It is pretty stable no major upgrades in versions any more. If you are tech savvy then you may want to install Trixie now. Who knows you may find a bug or two to report.
where can I find such info?
freebsd seem more transparent in this regard:
www.freebsd.org/releases/14.3R/schedule/