[BonusPlay]

Depends how much patience you have.

Firejail if you want ease of use (there are a lot of ready profiles to be used).

Bubblewrap if you want more security, at the cost of having to do more manual work.

TL;DR Firejail is a blacklist of things, while bubblewrap is an whitelist, so bwrap policies tend to be tighter.

[OJFord]

That depends on the profile, firejail supports both.