I ride a lot of singlespeed, and I really love it. My MTB and CX bikes are both singlespeed. I got into it while working at a shop that reminds me of the one you described!
If you’re doing a long-ish commute, then I’d say start with a more road-oriented build and expect that it will feel a lot different. Ideally you’ll spend a good month or so riding it as much as possible to get used to it. Enjoy the ride!