Tabs Outliner for chrome/edge is far superior than any other tab extension, and I've tried nearly all of them.

Looks like a separate window, so clearly not superior to Tree Style Tabs in Firefox.

Unfortunately due to limitations of chrome's extension model, there is no way to have a built-in extension sidebar like on firefox. I just manually position the tab window next to the browser window and it's fine. The window sizes are remembered and so it's really a non-issue.

Edge has had vertical tabs with tab groups natively for a couple years now. It also has a nice Reader mode, good text-to-speech, and a screenshot tool built in. And it supports uBlock Origin as an add on.

Yeah, that's not the same, or even functionally close. Just a superficial resemblance. The value of tree style tabs is that you don't manually organize anything, and the tabs are nested arbitrarily deep so that you literally end up with a hierarchical tree of tabs that shows you the logical view of your browsing history with no manual input on your part. (Note the comparison to edge has been made before, which is why I specifically said tree-style tabs, not vertical tabs.)

Longtime ff user, I use "Tab Groups Extension" for Chrome at work where ff is not allowed

What kind of work allows Chrome, but not Firefox? Google?