I go to Santee for business. Santee is not 10 minutes to La Jolla. First you drive about 15 minutes on crowded Mission Gorge and then you have to drive about 25 minutes the whole length of 52 to the west.
The afternoon into Santee from San Diego is a nightmare. I drove it a couple of time and I won’t do it again.
The Santee Town Center does have all the big box stores and the last stop on the trolley line. But the trolley is so slow that if you think you can commute to Downtown on the trolley, you’re sadly mistaken.