Firefox Multi-Account Containers ("container tabs") together with Temporary Containers[0]. Every tab is as isolated and ephemeral as possible unless there's a need.
I also use profiles, for work and leisure. Mostly for differentiating extensions and the data they get access to (no container tabs at work, and very few extensions there overall), but also for bookmarks.
I also use profiles, for work and leisure. Mostly for differentiating extensions and the data they get access to (no container tabs at work, and very few extensions there overall), but also for bookmarks.
[0]: https://addons.mozilla.org/en-GB/firefox/addon/temporary-con...