Why is ‘every day’ the lowest setting to remove them automatically and not when I close the app?

Instead you can use the “Delete browsing data on quit” feature but only enable “Open tabs”, tho this feature by design only works if you close the browser by pressing “Quit” from the 3 dots button on the toolbar

use 7zip zstd!

Despite turning off settings to open new tabs, every website I open browsing on mobile opens a new tab

That shouldn’t happen, I’ve just set Homepage > Opening screen to last tab and when I open firefox it defaults to the last tab that I was on before exiting the browser

I had to adjust a ton of settings to stop it from downloading in the background every file I just wanted to view or print

Iirc its just setting browser.download.open_pdf_attachments_inline to true at about:config