Agree on: the trend to get GPS data from a smartphone is particularly irritating (either drains power on the phone, or you forget to enable it). I miss the 6D/6Dii built-in GPS.
I hadn't thought of sensor shift star tracking. That'd be useful, assuming it would work with, say, the R6.
Having owned several cameras, each has pros and cons in its GPS approach.
Canon EOS 6D: Standalone GPS receiver on the body. Takes a long time to get first fix. Weak signal on airplanes. Heavy battery drain. Does not work underground or in big buildings.
Canon EOS M6: Post-shooting tagging with GPS when camera connects to smartphone, using timestamps for correlation. Smartphones are extremely fast (e.g. A-GPS) and accurate (e.g. GPS+GLONASS), can use Wi-Fi for indoor geolocation, and can tag basically 100% of photos without missing any. The cons are the need for accurate timestamps, the need to keep the phone on and logging (potential high battery drain), and the need to manually invoke the sync action after shooting.
Canon EOS RP: Bluetooth connection to phone. The phone's geolocation is fast and accurate. But the Bluetooth connection is terrible; takes 5~10 seconds to establish; cannot geotag missed photos after the fact (unlike the M6); the phone has a tendency to evict the Canon Camera Connect app which means no Bluetooth connection to the camera.
That's the thing that's most baffling to me. It seems like GPS as a feature would cost nearly nothing in money or space inside the camera, but it's still extremely rare. Pentax had it in the K-3 II but dropped it for the K-3 III.
I hadn't thought of sensor shift star tracking. That'd be useful, assuming it would work with, say, the R6.