I would join a local club and see if anybody’s interested. Not many people would at festivals/knocking at Universal or even A24 would try to read a screenplay unless you have a couple other film’s acting kind of as your resume (that doesn’t mean you should try!!)
In the meantime, I would practice becoming a filmmaker yourself. Teach yourself the basics of rule of thirds, composition, focus on sound, practice editing, and make a couple of shorts using your writing skills. Take your friends and make it. Some of the people I collaborate the most are the very first friends who I started shooting silly shorts with. Take time and have fun with your friends, it’s a short. They will genuinely feel like they’re having fun so that when you shoot your big project, they’ll be more than happy to hop on and help out.
Through this kind of practice, you’ll gain experience and your friends will possibly suggest a couple of friends that know a thing or two. You would be surprised at how many people your friends potentially know who have a background in film/theater. Sure you’ll have to wait a bit for the chance to show off the big screenplay, but I guarantee you that gaining experience in just making movies regardless if you don’t want to be the director is a necessity.
Damien Chazelle, the director of La La land, found his first big break after he made the short “Whiplash.” Then, it premiered at Sundance or something and he got funding for a feature. He made the feature Whiplash, which then proved to studios that he could something as big as La La Land. (You might have known that but still, good story )
TL;DR, gain experience making movies, use the people around you, prove yourself to others. People will naturally come towards you. You may not think you’re making any progress in the first couple months, even year, but if you keep on doing it, I can guarantee you will be able to turn your screenplay into a film. (Or like I said earlier, just pick up a camera if you already have experience and shoot it)
Btw, I’m an amateur, I’m a high school student who’s just been making little shorts/series for about 2.5 years. So I’m not a professional.
Hope this helped and good luck.