I lent my cycling GPS (Wahoo Elemnt) to a friend to record his lap of the local track. The information recorded was interesting, he said, but, perhaps, not that useful!
I uploaded the information to Strava. From that lap speeds, times and elevation could be seen. Also a map of the route.
It generated some interest at his club the afternoon he was using it, he phoned me to ask how to reset the device to record someone else's journey, ended up recording several other loco journeys and my friends drive from the track to my home!
Strava (other GPS apps available) can be uploaded to a phone to do exactly the same as I described for zero cost for the basic and entirely adequate version. It will give real time info, more or less, during the journey. I have noticed that these GPS devices don't quite have the transient response of the old school cycling "computers". The GPS devices are processing a lot more data I guess?