I’m going to choose a VM.

Tried it several times! Didn’t fix the issue…

I don’t think mintinstall lets you change where you’re installing the program… Interestingly, I ran flatpak search libreoffice again and it quickly returned some packages, which it didn’t do before. Still can’t install anything though…

Linux Mint is supposed to come with Flatpak support by default. Running flatpak remotes shows that I have flathub configured:

Name    Options
flathub system

That said, thank you for answering! I appreciate it, even if it doesn’t solve my issue.

Some websites display warnings even though everything works fine, like web.skype.com. But that’s the closest thing to doesn’t work I’ve ever seen on Firefox.

What about Apple’s WebKit? Does it count?