If you receive the error:
PHP Warning: session_start(): Failed to read session data: user (path: /opt/alt/php73/var/lib/php/session) in /home/xyxyx/public_html/libraries/joomla/session/handler/native.php on line 260
When switching to PHP 7.3 with PHP selector, its possible that you ran into a bug; the solution is in that case easy enough:
Make sure the system operator reloads the following:
yum install alt-php73-mysql-meta
client may need to go to PHP Selector and enable MySQLi there as well.
