Thank you, all! I really appreciate your insights!
I have ordered from DoorDash, etc., but I am still a newbie in using those services. I am sure, based on some of the many helpful posts in this thread, that there are ways to do what I need to do but I just did not know how to do it. When I used DoorDash to see whether I could narrow down which SF ghost kitchen would fulfill the order, I was actually prepared to drive to wherever I needed to go to accept the food delivery order. (I had multiple shops in SF for the day in question.)
I had much better luck doing some ghost kitchen shops in Oakland because there was only one Oakland location. There was no way I could mess those assignments up and I didn't mess them up. The physical restaurant location was also one that I had shopped multiple times, in person. Four or five different ghost kitchens worked out of that one restaurant. I have not seen those shops for many months or I would gladly do another.
In terms of the quality of the food, I must agree that it was not worth the high prices. OTOH, I have been lucky that one or more items in each order were usually above average. Not worth the price, certainly, but at least it was not so bad that I regretted doing those shops.
Thanks again for sharing your knowledge.