> There's no clean mechanism to control a fan's speed in-band on a normal AC wall switch.

I went through this pain when I bought ceiling fans a few years ago. Various manufacturers offer switches or remotes you can attach to the wall but that take batteries - the options for actual wired switches are slim. I ended up with a few hardwired Big Ass Fans wall controllers that work pretty well - but their current-gen wall controls are hardwired bluetooth remotes, which is subpar for something that's connected via wire. (And they cost $210/each, which is pretty egregious for a wall switch.)