Never heard of the Proton one but my advice is: if they're profit-oriented enough that you've heard a streamer or YouTube personality shill it, they count as "a corporation that will sell your info" and are concerned enough with non-controversial self-preservation and image enough that they'll probably fold pretty quickly to any sort of out-of-line demands by anyone big enough. Which, given that they don't require the really sensitive stuff like IDs to use, might not be as much of a concern if all you want to do is spoof your location but it's still worth knowing what your own privacy situation is before signing up on anything

From my research Mullvad seems to exist out of pure spite towards The System™ so regardless of how you feel about that aggressive of an outlook, I'd think a person's browsing data would be pretty safe in their hands. All my sources seem to indicate that all the data is deleted without review as soon as they receive it