I've had an M10-P since the beginning of 2019, and it's my primary camera. If I was limited to only one camera body, it'd be an M10. However, I just bought a used SL (and M adapter) specifically for shooting portraits/people with strobe.
Nailing focus with a narrow depth of field is difficult (for me anyway) with a rangefinder alone. I'm better at it now, but it takes a long time. On the M10, I can use the external EVF and dial in the focus, but then the hot shoe is occupied and I can't trigger strobes.
With the SL, it's pretty simple to focus just where I want reliably. E.g., I shot portraits of a friend last week with a 50mm Summilux-M at f1.4 using the SL, and didn't miss any due to focus. I was using strobe too (with an ND filter on the lens) and feel that M glass on the SL is a very useful combination.
But even with M glass, the SL is a chunky beast. If I'm walking around (i.e., not in a controlled studio environment), the M10 (or any digital M) is far better in the hand. I'm not dedicated enough to sling an SL2 over my shoulder when stepping out for an errand. But I can do that with the M10.
To me, the main differences between the SL and the SL2 come down to three things. First is the higher resolution, but 24MP is pretty amazing already. Second is better video features, which I don't think I'd ever use. Third is IBIS (In Body Image Stabilization). That's an awesome feature, and I'd love to have it on the M10, since that's the camera I use in limited light. But it'd probably go unused for me on the SL2, given how I'd use the camera.
IMO, the SL is still an amazing camera and now is a great time to buy a used one. The market is flush with SL sellers who want to trade up and the prices are quite reasonable for what you get. Most of the "Leica tax" has been squeezed out.
For me, a used SL was the better choice and I "saved" $4000 USD versus buying a SL2.