> Also ad blocker support is limited.

Try 1Blocker or AdGuard Pro. And similar limits (for similar "this shouldn't run that there" reasons) just arrived for the Chromium family.

> needlessly slow

I tend to find that when I notice slowness, I have several hundred tabs open, approaching the 500 tab limit. Save all tabs to bookmarks, close all tabs, and I find it's as "snappy" as the new iOS meme. (Related? New device, no tabs? Hmmm...)

Super annoying this hasn't been resolved since introduction of cloud synced tabs.