Right now I just have a raspi hosting superset and sqlite for me and I use it locally, its not out in the open. However, based on my experience, the metrics and dashboard for the car are not very hard to do, the biggest factor imo is the discipline of data collection, get receipts and insert data to the db for each refuel, maintenance, parts, registrations, insurance etc. If you miss collecting data, the data/insights aren't as useful anymore. Maybe scanning receipts and ocr is the next step, that's on my roadmap, when I find time that is :)