The left pedal is natably faulty - the axle is stiff with poor or no power reading. Both pedals have wear on the beds and squeak.
Garmin Rally XC200 Dual-Sensing Power Meter Compatible with Shimano SPD...
Garmin Rally XC200 SPD Dual Sensing Power Meter Pedals
Garmin Rally RK110 - only used indoors
Garmin Rally RK200 Dual Sensing Power Meter Pedals
Garmin Rally RS200 Dual-Sensing Power Meter Measurement SPD-SL Pedals