Latest phpMyAdmin versions require mysqli extension and will no longer work with mysql one (note the extra “i” at the end of its name).
For PHP 7.3
sudo apt-get install php7.3-mysqli
For PHP 8
sudo apt-get install php8.0-mysqli
Will install package containing both old one and the new one, so afterwards all you need to do is to add
extension=mysqli.so
in your php.ini, under the subject Dynamic Extensions.
Restart apache:
sudo systemctl restart apache2
Authenticate if needed and press enter.
Should be done! If problem still occurs remove the browser cache.