If you want to use a web browser on reasonable secure way, you could use firejail:
https://wiki.archlinux.org/title/Firejail
It’s not as powerful as @qubesos but it’s well enough:
Eg.I run @librewolf with firejail using firefox profile:
firejail --x11=xephyr --xephyr-screen=1024x900 --net=wlan0 --seccomp --caps.drop=all --nonewprivs --noroot --profile=/etc/firejail/firefox.profile openbox --startup “librewolf”
you can set up a symlink and create your own librewolf profile for it.
kde has a GUI in system settings for firejail/firewalld
Web browsers have some of the most security out of any applications out there. What, specifically, is firejailing going to do?
Also if your goal is security rather than blanket privacy, Chromium browsers are better: https://madaidans-insecurities.github.io/firefox-chromium.html
@OsrsNeedsF2P perhaps what I achieve is not spying what I type and where my cursor is.
I will not enter to blame wars. But trusting in a very evil company is a bit ironic (don’t you remember when they scan open wifis with google maps cars?)