Wait a minute. You are a Mavic 2 flyer and have never been prompted to calibrate the compass by the DJIGO4 app? This seems crazy as there is a forced message every 30 days when you are flying the Mavic 2.
Been flying mine since about 2 months after the initial launch and have never calibrated it in all this time. No request every 30 days a you state for yours, at least not from mine.