Hi! I don't see anything new in upstream https://jira.mariadb.org/browse/MDEV-28751 about this.
However we do have MariaDB 10.11.1 in Debian now. Maybe you Daniel can for the sake of it check if the behaviour is still same on 10.11? I would personally also be keen to figure out how to make the MariaDB datadir be able to run off overlayfs or something similar so I can implement my long time idea to have shadow upgrades where the old mariadbd and old data is kept running and intact, and every new version mariadbd would first run off overlayfs with real data to simulate the upgrade before it is done for real.