how do you distinguish between saying for example “A person he likes” and “A person who likes him” if they would both be 彼が好きな人？is there a way around that? different wording? a different particle? i must be missing something here hahaha. any help would be appreciate!
Both meanings are possible with 彼が好きな人. It'd have to be decided on context, but if someone were to hear that out of the blue, they'd be far more likely to think that it means
A person he likes.
If you really wanted to unambiguously say
A person who likes him, the best way is probably by saying 彼のことが好きな人. There are other ways such as for example saying 彼を好きな人 (An interesting use of を where it typically isn't allowed).
Here's a great other answer on this: