@SheriSim57 I like what you did with your lot! I have the same problem. There's only so many lots you can use as a generic lot. I wind up adding a building to whichever park, such as in Newcrest, to add my career offices.
I like the idea of what you did with Waterside Warble! Its actually one of my favorite lots in San Myshuno. The building has ample room upstairs and has such a weird layout, that you can adapt it for any number of builds.
I agree with @crocobaura I think only some of the food stands will work according to a schedule. Some are seasonal so that can have an effect too. But I have generally found that at least one or 2 will spawn vendors if you have multiple.
The community lot setting is great for these career builds too! Especially if you add all the items to the build so you can switch between different lot types (market stalls vs community garden vs maker space vs generic etc.
I will switch to a generic lot for this kind of build if I'm playing a career sim. Sometimes the community center lot spawns so many NPCs who manically use all the items you may need, it can be difficult to finish daily tasks. Although community center lots are fun to visit if you are traveling with a group of friends or a family of sims. They can be dynamic and great place for screenshots, meeting other sims, or watching wacky interactions :)
I'd love to see some of you Generic Lot/career/community lot builds too!