https://addons.mozilla.org/en-US/firefox/addon/force-1080p-n...
https://chrome.google.com/webstore/detail/netflix-1080p/cank...
Tab Set-aside, the thing where you can suspend tabs and then bring them back later, instead of having a browser with dozens of open tabs all using up memory.
It integrates with OneNote and pen input, you click the "add notes" button and the open web page turns into a screenshot with a OneNote toolbar for highlighting and drawing on it, which can save or share the note.
It has that dropdown tab bar preview thing which FireFox has only recently sort-of-cloned in its alt-tab-with-previews feature.
It sends your browsing history to Microsoft by default.
for a tablet-style browser it is more tablet-y, large-buttons, touch-input focused than IE11 was, so even if that's not innovative or distinguishing it fits Microsoft's dreams for Win 10 a lot more than IE did.
I'd never heard of this, so I thought I'd give it a go: it's not on the right-click menu but on a separate icon on the top left, where the System menu should be so I'd never looked there. It turns out to be handicapped by not being able to save/restore individual tabs, you can only push all of them off and then restore ones you want.
Edge is rather hostile to tab-heavy users in other respects - it doesn't restore them after close, and it just makes them smaller and smaller without any kind of scrolling. So beyond about 20 tabs it becomes hard to use, and you'd never reach 200.
As for tab-heavy users, I find FF Quantum to be horrible in this respect, and I keep missing Chrome, which allows a ton of tabs and resizes them, albeit slightly unreadable after ~40-70 tabs, but at least I can see the icon, which is usually enough to find what I'm looking for. FF resizes until ~5 characters of the title are still visible, thereafter requiring "< >" arrows to scroll through tabs... unfortunately if you click one of those arrows too fast (twice in < 1 second), it will skip 10-20 tabs or jump to the completely opposite end(!), which can be frustrating to get back to the tab that is just barely hidden off-screen. I have seen this complaint in forums but still haven't found a reliable workaround other than editing some javascript relating to the default theme (I forget the details)? I have reverted back to tab/ctrl-tab to cycle through tabs.
I use Tree Style Tabs.
It's a pity firefox still doesn't support it properly by allowing the top tabs bar to be hidden without userChrome.css hacking. I just ignore the top ones for now.
Regarding Tree-Style Tabs... I wish I could agree with you, I have been trying various Tree-Style Tab plugins on multiple occasions over the years, often for months at a time... before always giving up out of frustration and resorting back to tabs on top. I honestly can't tell you the exact reasons, but it's generally a frustrating experience... initial transition takes a couple days, plus issues like lack of proper hotkey support e.g. tab/ctrl-tab for tab switching, ctrl-f4 to close a tab, ctrl-t to open a new tab, some or all of those hotkeys tend to not work properly. Multi-screen support was also... lacking, for lack of a better description. There were various other minor annoyances and quirks with every plugin... and I tried various plugins for FF and Chrome before ditching all of them. I will probably try again soon, now that FF Quantum has been out for awhile, hopefully more plugins have been created.
So for me, the fact that I don't need an addon to do that would definitely have sent me to using Edge over Chrome or current Firefox, if I were on an OS that included it.
Over time, I've found that (in general) Microsoft is less prone to breaking what has already worked than Mozilla or Google. I don't know about Apple beyond iOS, and I don't know about that for the backend, because on the iPad, the only non-OS Apple software I use is iBooks (hasn't changed much in terms of 'tap a book, read a book'), Notes (hasn't changed much in terms of 'open a note, type a note, it autosaves'), and Podcasts, which also hasn't undergone much change. Heck, it's the App Store itself that's most broken for me now, to the point that I've come to rely on sites like appapp.io when I want to find a program or game; and then I pop over directly to the app store page for the software. With Google, I'm glad I never used GMail in the first place because I've heard the redesign is terrible. Maps are still pretty good though there's been some new "features" that made my life more complex; but every new version of Android that I get when I change mobile devices seems to bring with it a new host of settings issues and things it doesn't allow me to do without rooting it. Mozilla, well, let's just say the downturn started when Australis was mentioned and there have been no significant bright spots (Pocket, the introduction of telemetry, & Mr. Robot being significant lows).
Sorry for going a bit sideways to the topic, but honestly, TL;DR: different strokes for different folks. I hope you genuinely like your desktop ebook reader of choice so much that you wouldn't feel a web browser can do the job as well, but I don't need the heavy-duty support of a separate reader program when the addon or built-in feature works for my needs.
To me, it's the decision to shove that functionality into Edge that feels like a typical developer shortcut: they wanted ePub, and ePub is basically HTML, and Edge already does HTML, so let's do a reader as an extension! But it doesn't really make any sense to me UX-wise. Again, the only reason for something to be in the browser like that is if you routinely open documents of that type via links. And I just don't see people doing that with ePub - note how your scenario doesn't involve anything of a kind.