Best practice, removing admin access from many websites hopefully this is not a repeat question, not sure how to search for this.

I run over 50 websites, not all are on the same server but some do hold many users together. Not all our servers are ours, some are ones we inherited.

Now say you have a developer who is admin on a dozen of these sites, is there an easy way to add/remove developer access to multiple servers across many domains in a low-effort manner? I'm looking at Drupal access but also SSH/cpanel access, database passwords and many other related passwords [LAMP systems].

It is a pain, as you know, to have to change all passwords on all systems when someone leaves and I was wondering how other people/organizations deal with this issue?

Thanks for any recommendations or thoughts you might have towards this!
Maybe you could use Drush for these operations, such as change passwords for admins ? Also to write a script with several drush commands, which would run via SSH console.

Unfontunately, I am not expert in writing these scripts, but I think that you should look in this direction.

For Drupal 8 another solution Drupal Console has been developed.

P.S. Drush and Drupal Console hardly work on virtual hosting. If you decide to use it, you will have to host your site on VPS as least.