

Reitti displays data coming either from an import. You could upload GPX, GeoJson files or export the data from google maps and import that. If you want more up to date data, you could install an app on your phone which pushes your latest locations into Reitti. GPSLogger or Owntracks are at the moment supported for that
Someone would need to get that data out of the app. Either as GPX or some other format. I do not think these devices are able to send the position to some configurable endpoint. A quick search for nut tracker and home assistant does not yield any reasonable results.
I think we are out of luck at that point. But maybe someone knows about a more open tracker device which could be configured.