Thanks Wouter for reporting this and Michael for submitting a merge request for a potential fix!
The libcrypto.so.3 is from the OpenSSL package. In your upgrade case it seems to be switching from libssl3 [i386] to libssl3t64 [i386]. Your MariaDB packages are amd64. This makes me wonder what is actually going on. Were you able to recover? Can you now run manually 'systemctl --system daemon-reload'? This is the line dpkg was most likely running: https://salsa.debian.org/mariadb-team/mariadb-server/-/blob/debian/latest/debian/mariadb-server.postinst#L289
