If you do not have physical access, it is not yours. Trust absolutely no one.

Oops. I got confused

Why do you think it is not useful?

I replaced Firefox system package with Flatpak because I think browser is the most used and vulnerable thing in my system. And the size seemed reasonable.

I did not replace Thunderbird because its size is almost 10 times.

Oh, so flatpaks cannot automatically get system themes?

If it is trial and error, is it really useful for a normal user?

I installed flatseal but I never understand what is essential and what is not.