wordpress in nginx docker container connected to php:8-fpm container and mariadb container isn’t creating any tables on plugin activation

Not sure if it is related, but just in case, as for the last time I looked at it WP core 5.8 have bugs in dbdelta relating to MySQL 8 when integers are involved. Latest MariaDb seems to do better.

I would assume that as of 5.8 core is not ready to be deployed on edge everything. There might be good chance of things generaly working but you might run into edge cases in which they will not.