That question came up to me, when recently working on one project I needed to restart my PC several times. And therefore, while I used 3-5 web apps I needed to log back in to each one of them again, after each restart. And I started wondering if privacy-wise that auto-clear feature is worth it or not? Has anyone maybe tested that?
You may want to start using Tor especially for your current Librewolf use case. Compare fingerprinting
Or mullvad browser to blend in with the crowd