If you want to get back into the hobby cheaply, go for one of the prosumer kits, like the Nikon 3xxx/5xxx/7xxx series, or whatever in the Canon line is comparable. (I'm heavily invested in the Nikon F system, and as a hobbyist can't justify investing in Canon as well, so I don't really know anything about their lines.)
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.
I had no desire to live with the limits of film again, I just thought it might be a cheap workaround. Ends up not being the case. I really cannot justify spending at all right now but I have looked at the prosumer stuff you mentioned. While they are good for the new cost there are a lot of compromises and each iteration seems to remove some obvious feature like a remote port or ISO button etc as they keep shoving old guts into new bodies and optimizing production costs. The math always works out cheaper to get used stuff with more appropriate specs when/if I can afford to do anything at all. Rather than spend twice on a kit then upgrading, it's more sensible to buy once and keep that stuff as long as it is physically possible to maintain it. My hopefully "buy it for life" rational desire is a Canon 6D Mark I, a fast everyday zoom, and a really fast prime for the stars. Some day.
Give it a couple of years. As I mentioned elsewhere in the thread, mirrorless is already starting to displace mid- to mid-high-range DSLRs into the used market, and by then it should be displacing the high-end stuff too.
(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.)
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.