I gave up riding spd years ago and haven't looked back since, I use two different flat pedals on my bikes.
For my Gravel and Mountain bikes I use DMR V12 pedals, which I find brilliant. They do have quite aggressive pins though, which is great for keeping your foot in place, however not so great for the soles of your shoes, or your shins! These are technically serviceable if you can find the service kits.
For everyday riding I use a less aggressive flat pedal on the folding bike, the snappily titled Shimano PD-EF202 pedal. Whilst I'm not sure I'd want to stand up on them in the rain giving it the beans uphill, they are in the main, great for everyday commuting and riding and I believe they are serviceable, though I've not had to try yet.
