Help - power meter confusion

I want to get power meters for my mountain bike and my wife’s gravel bike. I took them both to a bike shop and after looking at them and doing some research, the mechanic concluded the cheapest option would be power meter pedals. Not stoked on the price of those, and I don’t think putting power meter pedals on my mountain bike is a good idea given how much I pedal strike (its possible on my wife’s gravel bike). Is there another solution that the bike shop didn’t recommend? I just don’t understand BB, crank, and chain ring standards so I find this space extremely confusing. Do I need to swap out the whole crankset if I want to go with a stages or similar technology?

My bike is a 2019 Specialized Epic Evo Expert with a Truvativ STYLO crankset. SRAM DUB threaded BB.

My wife’s gravel bike is a Cannondale Topstone Carbon 105. Cannondale Allot PressFit30 BB, Cannondale 1 Crank with FSA rings.

Thank you for any help you can offer!

To get a cheap crank arm power meter, you prob have to have the entire crankset in those bikes. So the mech is right that the easiest thing to do is to buy pedal based. Don’t worry about pedal strikes, they are robust.

Try Sigeyi PM’s. Have one on my MTB. Quarg on gravel bike. Assioma on road bike. :person_shrugging:t3: