I want the player in my project to have a cone of vision and not be able to see of it, so far i have had a sprite that hides/shows things inside the cone but that allows the player to see through walls which i dont want

You could have a set of projectiles that clone and launch from the player, and get stopped by walls, then the other things can set their Ghost effect to 0 if they're touching those projectiles, or to 100 if they're not?

Here's a quick mockup: https://scratch.mit.edu/projects/1048303132/

Thanks! thats really helpful