When I change the oil I always fill to between low and middle on dipstick,That is the useable range, I have had the sump off a couple of time to check oil pick up for debris, and it is always clean.
I dont do short journeys, I go to work on a Monday morn with a full tank, and drive 120 miles, 50 of which is at about 80 mph, and the rest is not hanging about.
Then return at the end of the week.
Are the rubbers and seals prone to leaking
Steve