Your graphs looks pretty similar to mine using a similar Assioma/Kickr18 setup with power match. The variation is relative to how smooth you are at delivering the power and your selected cadence. I think of it as trying to cancel out a wave - if you stay consistent the software has a better chance to correct.
I don’t know about both pedals - that might change depending on Ant+/Bluetooth connection type. It is discussed here: which might have some more information.
https://www.trainerroad.com/forumt/favero-assioma-duo/13562/8?u=jdv