Film has become extremely niche in the last decade, even among the niche that is interchangeable-lens-camera hobby photography. As you've seen, that makes it expensive.
That said, if you're looking to get back to film specifically as opposed to photography in general, you can find good used midrange 35mm bodies without too much trouble. You'll still pay through the nose for film and developing services, and probably also for glass since that holds its value in a way 35mm SLR bodies don't, but you can at least avoid the $2600 bite of a brand-new F6.
(And I feel you about the UI issues. Part of the reason I switched from a D5300 to a D500 was because the prosumer bodies are really designed to be shot in program auto, and you just don't have enough direct control of basic parameters - you need to be in the 7xxx range even to have an aperture dial! I'm waiting for D850s to start hitting the used market in numbers for precisely that reason - 45MP full-frame is just about ideal for the macro work I do, despite the relative DoF loss, and the UI commonality between that and the D500 means I won't have to worry about missing the perfect shot of a wasp or whatever because my hands got confused about how to operate the camera.)
If you can avoid getting swept up with the idea that you need the latest and greatest, it's a really great time to get back into photography. eBay is full of fantastic kit at yard sale prices.