Thanks Andreas for testing potential changes! If you file them as MRs at https://salsa.debian.org/mariadb-team/galera-4 and https://salsa.debian.org/mariadb-team/mariadb-10.5 you'll get the additional CI testing run on top of the for free for extra validation. There is a mariadb-10.5 Bullseye update pending already, so this is excellent time to put in more changes as long as they are justified (these are).
We also plan to make a mariadb-10.3 stable update to Buster, so putting a critical fix is also an option.