When I touch a public surface differently than a private one, I try to do so with something less gross than a shoe might be. I use knuckles or elbows for walk-light buttons, for instance, and a knuckle on the touch screen at the public library or an elevator button. I'll press a door lever with an arm, maybe, hold it open by leaning on it, that kind of thing. The knuckle thing is because a knuckle is less germy than a fingertip (especially if I wash hands before leaving home), so I am spreading fewer of my germs, and I am also less likely to put my knuckle in my mouth or eye, so whatever germs I pick up are less likely to get anywhere dangerous. And I don't think anyone is more grossed out by knuckles/elbows than fingertips, while I'm very aware that lots of people find shoes more inherently disgusting than I do.

Toilet handles/buttons and restroom door handles I don't worry about as much, as I'm just about to wash my hands again anyway. I do sometimes press a toilet handle with my knee, I think. I don't recall ever getting noticeably sprayed.

Since Covid started, I have tried to keep the habit of washing hands just before I go out and just after I get back, as well as at the obvious times like using the restroom. I also carry my own soap most of the time, because I used to avoid public restroom soap as it nearly always smelled horrible.