@js that said, if you have a bit of time on your hands and are interested in building a small collection of published apps for your portfolio, one app that I know would be popular in Japan (and probably elsewhere) would be a better dash cam app. Something that records video and time-stamped GPS locations, allowing an export of that GPS data afterwards to put up against a map.
There are some apps available that will sort of do this, but they all want $60 a year in subscriptions and the apps look like something from the days of Microsoft Bob … which does not work on a mobile phone 🤪