I've found that tracking only works if QField is active and the screen is turned on constantly. This drains battery power. As soon as the power button is pressed to conserve the battery the tracking stops and connects a straight line to the next location when QField is activated again. I am using a bluetooth GPS and have tried Lefebure Design's NTRIP Client as the mock location provider.. despite this you still have to turn on location services for QField to pick up a location. MapitGIS is able to use the mock location provider and it's own GNSS settings to the bluetooth device while recording tracks whether the phone is in sleep mode or not.. this is how most GPS tracking devices work normally (eg Garmin eTrex devices). What is promising about QField's tracking feature is that you can still take points while it keeps tracking.

a) Is there a way to keep the phone's location services turned off but to pick up the location from the mock location provider (eg from Lefebure Design's NTRIP Client)? With location services turned on and airplane mode turned on it does seem to be using the bluetooth device in some way but it theoretically should be able to simply use the mock location provider and leave location services turned off completely to ensure it using only the external bluetooth GNSS device.

b) Is there a way to keep trackpaths tracking when activating sleep mode to conserve power on the device? We typically are out for 8-10 hours surveying and need the trackpaths capturing data every 3 seconds.