Job queue stuck after server changes

Hello, I first tried searching for help but couldn't find anything that I understood clearly; I'm pretty green.

I'm running Ubuntu 16.04.6 and ISPConfig 3.1.15p2.

Background:
This morning I set out to add a different version of PHP to ISPConfig.

Beforehand, I added the ppandrej/php repository, ran apt-get update and things went well. At the end of this, when I run php -v it says it changed to 7.4, while previously everything was running on 7.0.

ISPConfig and all of my sites continue to work, and the sites report they are still using 7.0. However, I'm seeing job's stuck in the ISPConfig job queue. I suspect the two are related.

Troubleshooting:
When I manually run server.sh:

19.02.2020-08:54 - WARNING - There is already a lockfile set, but no process running with this pid (24711). Continuing.
PHP Fatal error: Uncaught Error: Call to undefined function mysqli_init() in /usr/local/ispconfig/server/lib/classes/db_mysql.inc.php:83
Stack trace:
#0 /usr/local/ispconfig/server/lib/app.inc.php(47): db->__construct()
#1 /usr/local/ispconfig/server/lib/app.inc.php(232): app->__construct()
#2 /usr/local/ispconfig/server/server.php(51): require('/usr/local/ispc...')
#3 {main}
thrown in /usr/local/ispconfig/server/lib/classes/db_mysql.inc.php on line 83
PHP Fatal error: Uncaught Error: Call to undefined function mysqli_init() in /usr/local/ispconfig/server/lib/classes/db_mysql.inc.php:83
Stack trace:
#0 /usr/local/ispconfig/server/lib/app.inc.php(47): db->__construct()
#1 /usr/local/ispconfig/server/lib/app.inc.php(232): app->__construct()
#2 /usr/local/ispconfig/security/check.php(32): require('/usr/local/ispc...')
#3 {main}
thrown in /usr/local/ispconfig/server/lib/classes/db_mysql.inc.php on line 83​

Like I said, I'm pretty green at this yet, but what I've gathered is that mysql package could be missing from 7.4, which is now being used?

Questions:

1. Can this be resolved by just a2enmod php7.0 and a2dismod php7.2 and restarting apache?
2. If not, would installing the missing packages for php7.4?

Any help resolving it would be appreciated.

 

You're the man! Thank you for the help!