Firefox tab recovery is getting harder and harder with each failure. For the first time I had to simply delete the current session lz4 file and boom recovery. For the second time I had to nuke any and every file with "session" in it to get it work. Now even the JS trick doesn't work and I have to manually open tabs with the help of scrounger. Shame.
I've lost some couple tabs to tab recovery and sometimes have to mess with .firefox/.librewolf too. You should do bookmarks
I just closed 3000 tabs in one browser, and I am about to do similar another browser with +2000 tabs. You should just delete the tabs
My advise is to structure your workflow around links, browsing history, bookmarks and memorization instead. browser.sessionstore is completely disabled in my profile.