You can search in forum, this is problem many years...:
https://www.aapanel.com/forum/d/5129-open-phpmyadmin-not-working-and-blank/2
No warning anywhere before, so novice users don´t know nothing without errors.
Change the PHP version to minimum PHP 8.0 in PHPmyadmin settings (install from appstore when you not see there).
When you have OLS, for plus points edit file:
/www/server/phpmyadmin/phpmyadmin_**********/config.inc.php
and line: $cfg['Servers'][$i]['host'] = 'localhost';
to: $cfg['Servers'][$i]['host'] = '127.0.0.1';
Restart OLS.