Chromium has site-isolation (with some caveats around phones with limited resources) so both Chrome and Edge have site-isolation. Firefox is getting very close with Project Fission [1] and I predict they'll ship it relatively soon. Currently Safari doesn't have site-isolation and AFAIK they have not publicly committed to anything in terms of getting there. They have done some work in this space (search around for Process Swap on Navigation (PSON)) but it isn't complete.