Meshtastic

Sometimes when I go cycling I take a buddy or two and we sometimes get split, and i was thinking that having something to tell me how distant we were from each other would be cool. Yeah, there are apps that do that, but they arent foss, they send your location to who knows where, and they massively drain your battery. I saw that there are some varriants of lilygo devices with gps and a screen, but how practical are they really? How fast do they update? How is the battery? Is somewhere using them for a use case similar to this one?