I didn’t know where to put this post, but…
When and how do the 'messages-<some-date>.xz files get cleaned up?
I know I can’t remove them as a non-root user, and some go back to the end of 2018, and some are quite large(2 to 5MB).
AFAIK this is configured in /etc/logrotate.conf and /etc/logrotate.d/