I use ~1200 tabs. I used to deal with what you and ksec experienced in Chrome by periodically killing all Google Chrome Helper processes, and a few months ago switched to Firefox (less sluggish) from Chrome. Last week I decided to try Chrome again and was pleased to find that (with the same tab set) Chrome 71 is amazingly fast; new tabs open instantly, I can immediately enter a search query or URL, and the browser remains stable over time. So it's back to Chrome for me; it is now only slow when starting for the first time, when it processes the 1200 tabs for a few minutes.

(I do use The Great Discarder, but did so before switching to Firefox, too.)