Is the ROTOR 2INpower road power meter compatible with 12-speed drivetrains?

Yes, the ROTOR 2INpower DM Road Power Meter is compatible with 12-speed drivetrains. For Shimano drivetrains, we recommend the ROTOR Direct Mount Road Chainring (which is the chainring that ships with this power meter by default). It is also available in an aero version here: ROTOR 110×4 Aero Chainring.

For SRAM, you would use the ROTOR 110×4 Aero Chainrings for SRAM AXS which are flat top compatible, come in round or oval and are available in 48/35 and 50/37 combinations.