Do browser apps run in a container/sandbox mode on a Mac?

Hi,

I learned not so long ago about “non-conventional” browsers for Mac, such as Helium or Arc browser and I was wondering how secure they are.

Do they run in a sort of a “container/sandbox” mode, meaning they can’t “see/read” what is open in Safari for example?

Can they "see" what the user is doing on the Mac in general or in another browser?

Not sure how to formulate this better, but as I understood, if say I have FB …

apps browser container mac mode privacy sandbox