OPEN PORT 3306 ON UBUNTU 20.04 SERVER WITH MARIADB

Login to the server via ssh

sudo bash

nano /etc/mysql/mariadb.conf.d/50-server.cnf

Uncomment the line:
#port = 3306

Change 127.0.0.1 to the address of your server
bind-address = 192.168.1.100

Save the file, exit, and either reboot the server or restart the service.