Shoes what kind?

Loads of MTB shoes here: https://www.chainreactioncycles.com/mtb/shoes-cycle/shoes-mtb

Various styles

They look fine ;-)

Ah OK. So you don't want to clip in at all?

Fair enough. Ideally you get a stiffer shoe if doing longer distances since a flexible sole is not very comfortable to cycle in and isn't very efficient.

You could consider something like this: https://www.chainreactioncycles.com/giro-rumble-vr-mtb-spd-shoes/rp-prod144385

It has a space for the SPD cleat but you don't have to use it.

I got a pair of those for some light touring in one of Decathlon's sales, due to covid they haven't got much use but they seem fine for what I paid for them. Fixed cleat position wouldn't be ideal for heavy use but they'll work well in flat pedals I would have thought.

Jaysus, you're not going to wear those with tights on a road bike, are you...

Some mtb flats have soles that grip better than "normal" shoes.

OP - I'd consider spd pedals/ shoes. Like a few have posted I use "touring" shoes for commuting, and I can drive in them (which I probably wouldn't in my "mtb" shoes. "Touring" spd pedals are pretty light release in my experience - too light for me when I've tried to use them on club spins. You can also get dual sided flat one side/ spd the other pedals - although do check the release tension on these (speaking from experience!).