How to Switch to Vertical Tabs in Edge Chromium - Lifehacker
We don’t know when the stable version of Edge will get the new tab menu, but you can install the Vertical Tabs Chrome extension for a short-term workaround that doesn’t require unstable versions of the browser—or others, if you’re not a fan of that add-on in particular.
The Vertical Tabs add-on does mostly the same thing as Edge’s, with one major exception: The normal horizontal tab menu is still displayed at the top of the browser, rather than just the vertical tabs.
I searched for a way to hide the normal tab bar in Edge’s settings and Vertical Tabs’ add-on configuration, but your only real option is to browse in full-screen mode (F11).
Based on my time with Edge’s vertical tabs feature and the Vertical Tabs add-on, I recommend downloading the Dev or Canary build and using that version if you’re keen on trying Edge’s vertical tab option early