Glide already has a column to calculate distance for you live and in real time. You don’t have to do the math yourself. Just make sure you have a column with an address or a set of coordinates of the client. Then add a Distance column to compare that’s address/coordinates to your current location. Then you can set filters or visibility (such a visibility of a check-in button, based on the user’s distance to that location.
Glide’s solution is much simpler and doesn’t require you to use the location component, or any complex math. Just an address column and a distance column.
While it is technically true that you can’t track live coordinates of a user, the distance column will still work without having to use the location component to capture a user’s coordinates.