Had struggled with this for 8+ years with usually 200+ tabs open, even started coding my own extension for this. And tried at least 30 extensions.
Finally settled on https://workona.com/ . It's not exactly perfect and I disable the tab cache feature via settings to basically open each workplace in a different window instead of replacing an existing one. But otherwise, it's perfect.
"I usually have at least 6 browser windows open with at least 10 or more tabs each. I wish there was a better way to do it."
Back when Opera was an innovative browser, it had a really useful tab grouping feature which let you achieve the same thing as you describe but without requiring a separate browser instance.
I wish there was a better way to do it.
I work on projects for a few days or hours at a time, and maybe only 10 of those tabs are relevant to a given project.
I'd like to be able to somehow only have the relevant tabs for my current project or train of thought.
Someone suggested I use the people profiles in Chrome which seems a good idea but obviously not good enough cause I'm not doing it.