You can do this with Firefox's containers. Containers are a Firefox built-in feature, but without a UI; install the "Firefox multi-account containers" extensio

You can do this with Firefox's containers. Containers are a Firefox built-in feature, but without a UI; install the "Firefox multi-account containers" extension to get UI for containers. There are also a variety of other plug-ins that do useful stuff with containers; search for "container" in the Add-ons Manager to see what's available.