Strange permissions issue

New multi-site install. Owner and group are both root for everything, so it makes sense that I can’t update or install new plugins from the WordPress admin using my account credentials. So, I changed owner and group to my user account (which has SFTP access to everything).

I change ownership first and I still get the message:

Removing the old version of the plugin… Could not remove the old plugin. Plugin update failed.

Then I change the group from root to my user account, and the plugins disappear from the WordPress dashboard. I can still see the files there because I’m SSHd in, but changing the group from root has caused them to vanish from WordPress.

And, changing owner and group back to root does not make them re-appear.

I know I can install and update plugins and themes manually via SFTP, but it would be nice to be able to use the dashboard.

I appreciate any suggestions for this Linux permissions novice.