All current-generation spider-based power meters feature OmniCal, which allows you to swap chainrings and crankarm length without affecting accuracy. Simply torque the chainring bolts to the manufacturer's specifications, and be sure to make sure Magic Zero is enabled in the power meter settings tab in the AXS app.
For current generation spindle-based power meters, the power meter is integrated into the DUB spindle and calibrated at the factory to the crankarm length it is fixed to. Since the power is measured from the spindle rather than the chainrings, chainring size does not affect power meter accuracy. Spindle-based power meters do not have the OmniCal function, and a rider should perform a Zero Offset before every ride for optimal accuracy. This can be done via the SRAM AXS app or compatible cycling computers. Nothing further is needed."
Exceptions
XX1 Mountain Bike Power Meter: A calibration adjustment may be required when changing from one chainring size to another on this power meter. If you are not changing chainrings, the calibration does NOT require adjustment. (This does NOT include the current XX1 Eagle power meter.)
Any Power Meter that uses a CR2450 battery: Any power meter that uses this battery size requires re-calibration when changing to a different tooth count or chainring brand. If you are not changing chainrings, the calibration does NOT require adjustment.
If you're unsure which power meter model you have, please contact Quarq Customer Service. When contacting customer service, please provide the power meter ID located on the power meter spider. The ID consists of 3 letters and 5 numbers such as; ABC12345 or 12345ABC.