Switching from SPD pedals to spd sl or other options..

I've used spd sls, spds and now look and I consider the unclipping to be largely the same movement. You can adjust the tension on the sls (depending on model) but I've no advice for you only practice and be conscious in advance of stopping and clipping out on one side as you slow down?

Think the OP is barking up the wrong tree tbh, if the cleat caused the injury (they didn't specify), then the issue was with the shoes surely?

The sole of my shoes is half an inch thick, i can't feel a thing through them, even on the ground it's like walking on air.

Good point too.

I have SIDI's OP, were well over a hundred euro at the time, they're not something i'd scrimp on.

I'd have no problem keeping the pace on flats.

My fastest 30k in the last few years was on flats in an adventure race.

I just find that after an hour i'm much more likely to get hot spots on flats than on my road pedals, probably down to the stiff carbon sole of the bike shoes.

I'm repeating a bit of above but i will anyway because it's worked for me

1. Move your cleats on your shoe back as far as they'll go. Not under your toes at all https://www.youtube.com/watch?v=3q3ASys6dOE
2. It's more than likely the shoes. Have a similar issue on old shoes (on Look Keos, like SPD-SL) and now have full carbon sole. The older shoes were cheap and flexed more was in agony after 50k, Solid soled shoes and moving cleats has fixed it
3. Have SPDs and Look Keos, exact same movement to get foot out of either.

Ah Look Keo are pretty much SPD-SL just a different manufacturer

I'd say reading the comments above that you have a different way of opening your SPDs?

Fair enough. I did guess something like that reading the thread, apologies OP

Standard SPD, SPD-SL release is automatic by now. Don't notice doing it.

Why not off-road exactly?

I find them perfect for off-road, when you crash your feet are never trapped, but there is enough tension for general riding/racing.

Never used the multi release cleats, but are they susceptible to disengaging if you're pulling on the upstroke?

OP, I've switched from SPDs to SPD-SLs, and back again as there was no benefit for me, and lots of annoyance (harder to clip in, rapid cleat wear, and moreso walking), from the SLs.

I've never had any issues with hot-spots with SPDs over the years and similarly found dis-engaging pretty much identical on the SLs while using them, so as others have said, it may be a problem with your shoes. Maybe a pedal with a wider platform would help (if you're using something like a PD-M8000 - below - for example)?