Is a 4th person perspective possible?

yes there is.

technically you could say there’s 5 if you count the two different types of pov in third person point of view.

there is first person point of view where you are inside the characters head using pronouns: I, me, my, we, our

second person it like your there in the story directly.

it uses the pronoun: you and your

and for third person point of view there’s two different types of point of views:

Third person limited and third person omniscient

third person point of view uses pronouns: she, he, they, it and etc.

both types use the same pronouns but

third person limited is where we know only what the character knows.

while in third person omniscient is where the narrator is all knowing.

but there is also fourth/five person point of view.

this point of view is also known as a shared point of view because instead of focusing on a single character it focus on a group of people instead of just a single person.

it uses pronouns: we, then, her, he, me, our, someone and etc.

the best kind of point of views to do are first and third unless you are wanting to write a book/story that is in a group setting or your writing a book that you want to write a book that’s in a readers point of view.

hope this helps.