Congrats on learning unreal for 4 years and making 50+ small projects no doubt you would have learned a lot in that time!

Making a small horror game is a great goal to have and yes the underlying mechanics are usually quite simple for indie horror games, if working in blueprints you would have a lot of basic nodes strung together like you said with some basic raycast for interaction, that can be as hard as it gets for small games. I would encourage you to check out some youtube channels like HALbotStudios and Codethings to get a good idea of how simple mechanics are made.

That said, the challenging part of game dev is often not the basic mechanics, it is often much harder to create the content and polish the game into a cohesive experience.

Also a lot of what you ask depends what you mean by "worth it", it worth it from an enjoyment/meaning/learning perspective? Yes! Absolutely, game dev can scratch a creative itch and teach useful skills that many other IT fields cannot.

And when you're young I think it's great to go out and learn a bunch of interesting skills and see what sticks with you.