I've done a bunch of debouncing switch inputs, keypad, keyboard, rotory switches. And wrote some test code for capcitive touch display (long time ago)

It's the kinda problem that will tend to bite you in the butt if you aren't aware of all the gotchas. Difficulty is they are application specific. But I wouldn't describe the code as particularly complicated.

Most of this stuff a crusty old neckbeard embedded programmer can do half drunk on Friday afternoon.

So because an expert can do it easily means it's easy? In that case literally anything is easy.

OP was saying that mechanical switches could be deterministic, which is something that I haven't experienced.

I do agree that there is less to go wrong than a complicated touchscreen interface however.