For me it’s down to anytime the bike leaves terra firma, I feel like I lose the pedals
This is kind of what I alluded to earlier- this isn’t a flats thing, it’s that you’re not riding with the bike whether on SPDs or flats. It’s just that with SPDs, you can drag the bike along with you (or it can drag you). That’s not ideal, it stops you from falling off but it’s still pulling the bike around and means you’re working against each other not together, giving the suspension and tyres a harder time
Really good SPD riders (which I was absolutely not, I should say, I learned all this the hard way) can jump onto flats and just ride. See: Gee Atherton, rides SPDs, can jump off the bike, borrow some five tens from a spectator, and race a dh world cup . Because riding with the bike is always best. So if you learn that on flats then take it back to SPDs, it’s a win.
(you don’t need to learn it on flats, you can learn it on SPDs. It’s just that flats will **** you up if you don’t learn, so you don’t really have the option not to learn)
Or, obviously, you can just carry on- it obviously works reasonably well so why stress? Nothing wrong with that approach