Yes, I have a Lidl MTB hard sole SPD compatible pair that are OK on flats but generally I would not choose a cleat friendly shoe on non clippy pedals. I've several pairs of now very dusty SPD shoes since committing back to flat pedals. The Lidl ones work mainly because they have a good thick ridged tread pattern akin to a walking boot and I prefer a quite toothy pedal.In my experience using SPD shoes on flat pedals is very slippy due to the hard cleat hole cover. Some sort of walking or trail shoe is probably best
My vegetables have Airwear soles which I think DMs do too. They're fine for cycling and brilliant for walking but you realise you'll be sacrificing a little pedal power and responsiveness as they're fairly springy.Doc martens