What I would love on iOS would be an isolated container like the Multi-account Containers on Firefox desktop. With a PWA, how are the cookies (and local storage

What I would love on iOS would be an isolated container like the Multi-account Containers on Firefox desktop. With a PWA, how are the cookies (and local storage) stored and handled? Do they all live with Safari's cookies? Or do they have their own cookie container that's isolated from the rest of the system? If it were the former, I wouldn't want that. I regularly use Firefox Focus (which is also the system wide content blocker for me), but it doesn't seem like its blocking rules are updated often. Not sure if that's because of some limit in the number of rules allowed per blocking extension.