Chromium Edge is getting vertical tabs, and from the screenshots it looks like a decent implementation. At the end of March, the blog post said it was coming to the Edge Insider Preview "in the next few months".

Animated screenshot: https://46c4ts1tskv22sdav81j9c69-wpengine.netdna-ssl.com/wp-...

Microsoft blog post (scroll down to #2): https://blogs.windows.com/windowsexperience/2020/03/30/the-t...

Vertical tabs with nesting, nothing less.