@brandon there are likely a number of things going on
If the drone sits idle for a period of time, the sensors heat up (accel and baro). When the props start spinning, the temperature drops causing significant drift. If you let the props spin for 10 or 20s cooling off the board, that can help
I would guess after 30-60s of flight, the altitude stabilizes. That is the temperature of the sensors stabilizng.
The latest SDKs have temperature compensated calibration for IMU and baro. Try calibrating accel and baro and see if that helps.
https://docs.modalai.com/calibrate-baro/
https://docs.modalai.com/calibrate-imu/
The GPS on Starling 2 Max has been tricky. We do have a new GPS on the way that looks promising, and hope to make it available in the next 2mo.