For me this feature is the only thing that is missing that makes me not migrate to use only Opera, I tried a lot of times, but without this feature, it's impossible.
When you start using Workspaces it seems that it will do exactly that, different sessions. But not, it's all the same session, so when you have more then one profile, like personal, work, etc. It's messy.
Besides it... Great job dev team, this browser is fantastic ️