I made something similar, basically a Fleet Management App but has some Uber like feature such as assign drivers to vehicles, add and plan trips, real-time analytics etc. Its serving ~15k vehicles now.
When we made it (~2009) we used Django for the webapp and Java (with Netty) for collecting GPS data. It was hosted on a VPS (RapidVPS, it was I believe we overspent behind the dedicated 8GB package), it served quite well. I don’t know what stack they are using now though but I think for small scale Uber clone starting with the more traditional approach would be okay like making the API layer with something like Phoenix, front end with React/Native that displays it and a message queue of your choice.