Thumbs down on Floorp
That's a weird one which I can't reproduce - Floorp and FF running happily together here.
If you still use r*ddit the dev is quite active and responsive there - /Surapuyousei. He may be able to offer a suggestion.
Vivaldi's tab tilling add-on in Firefox
Not the last time I looked (about a month ago). You can tile windows on your screen, but not tabs within a window.
