Most people consider power meters a road only thing. Even though part of the way you train with one means using a PM to capture the stress from all the riding you do.
I bought a pedal based power meter because it's literally compatible with every bike there is. I ride a Cervelo which uses BBRight and that means if I got a crank based PM, selling the bike and keeping the meter was out. Mine has been on 3 bikes I've owned since getting it, the first had caliper brakes, the next two disc, that ruled the hub out. To be honest Keo cleats aren't ideal even on gravel, I'd have to really want power data bad to ever try this on an MTB.
Power2Max has some good options.