Thanks for the detailed reply :)

I've tried setting up a separate profile on my laptop for the main site that I manage, but I'm finding the permissions to be difficult. I need to transfer files from my existing profile to the new website profile, but I keep getting all sorts of errors telling me that I'm not allowed, even if I put the users in the same group and give the group read and write access, or if I try changing ownership to the website user.

I've probably set up something wrong with the new user, but it made me think about other ways of doing it, and how to back it up. I'm probably going with a VM so that as well as a regular backup, I can back up the whole VM and store a copy on other physical computers. If something goes wrong, like my laptop getting stolen, I can just fire up the VM on another computer and keep working.

@mojo_raisin@lemmy.world had a good idea though, of using different themes and the logo to help differentiate them. I think I'll use that whichever way I go.

XFCE is a good idea, thanks. I use Xubuntu on my media server at the moment, so I'm used to the way that it works. I like the look of KVM too. Apparently it's faster than VirtualBox, and that's usually fine for my needs, so it should be good :)

Having different Firefox and Thunderbird profiles under the same login is something that I'm definitely avoiding. I've tried things like that in the past, and have trouble keeping them separated. I have some memory issues, probably related to ADHD, and find it too easy to open the wrong copy of a program when I'm focused on something else.