I use container tabs and tab search. I too have lots of tabs open.

Tree tabs (sideberry). I just never close tabs, old tabs are suspended by Firefox automatically, and I never shut down my pc, just sleep.

It's just a bad habit at this point x)

Not them, but tree tabs + auto tab discard is a great way to browse documentation when working on a project. That can easily use up dozens of tabs.

3000 seems excessive, but tabs are better than bookmarks since they save page state like scroll position, so many people use tabs instead of bookmarks. That's more a lack of useful functionality in existing bookmarks than an inherent advantage of tabs IMO.