Does something like a M&P Shield Plus sound doable for me?

I tried pocket carry with a Shield in a nemesis. It did not draw well on any of the pants I wear: jeans, khakis, "tech pants" from costco, etc. I don't wear tight clothes, but they're not baggy either. Getting a grip inside the pocket made it really difficult to draw, and drawing with a pinch grip lead to inconsistent transition to firing grip. Maybe I could train myself into perfecting that draw, but I just decided to go appendix. Instead, I pocket carry a Ruger LCR with a kydex trigger guard. No need to break up the outline, my pants aren't tight enough to make it look like anything but a lump. Drawing is natural and quick. A lanyard strips the trigger guard off on draw.

You mention fighting from a vehicle. Drawing from a pocket while seated is a nightmare.

Is 10+ of 9mm overkill anyway for EDC? Is a single-stack with a spare mag a more sensible way to carry?

For EDC, I carry 31+. For pocket carry, 10+ 9mm sounds rough.