Bear in mind that, regardless of how long the first GNSS lock takes, subsequently powering up the drone within a short period of time (2, 3, 4 hours, that order of magnitude) and within a short distance of the previous location will allow the drone to utilize cached data from the previous GNSS lock, giving you a much faster subsequent GNSS lock, 10-30 seconds.
Reading those steps, especially "5 - restart the aircraft", you're pretty much guaranteed to get a fast GNSS lock at that point no matter WHAT you did before, if it previously just acquired that lock, say during the IMU calibration step or while you were waiting for "strong GPS".
If you could return to those same locations, at about the same time of day after not flying for a few hours, and then time the home point confirmation, that would give you and us a better indication of any actual improvement, vs any assisted improvement you saw from cached data. Good luck!