Updates on my MacBook Pro 16 external drive are excruciatingly slow

You need to do more than just turn off. The install files that go active upon boot. You should uninstall them fully according to the developers instructions. Then you can check to see if you've removed all of the supporting files by downloading and running the shareware app Find Any File to search for any files with the application's or the developer's name in the file name.  For the two apps mentioned you'd do the following search(es): 

1 - Name contains cleanmymac

2 - Name contains macpaw

3 - Name contains clamx

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that you can't like invisible folders, system folders and packages.  

If you get a warning that the files are in use of used by another app boot into Safe Mode according to How to use safe mode on your Mac and and run Find Any File from there.

tinkerbelle2012 wrote:

Hello, since I updated to OS 15.5.1 on my MacBook Pro 16, updates (on my external drive, a GDrive mobile USB-c 2TB) are excruciatingly slow - about 1% every 10 minutes.

What do you mean by "updates"? Do you have a system on the external drive that you're updating?

Or do you mean the external drive is a Time Machine drive and the backups are taking a long, long time?

Are you sure you don't mean 12.5 like in your signature? 15.5.1 is an IOS release.

Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac?