The map tiles on osm.org are rendered in a priority stack. Some zoome levels are rendered more often than others.
Due to limited ressources of the donations based OSM server this can take a while.

If you want to support, don’t hesitate to donate.

The time you see your changes in Gaia GPS depends on how often OpenHikingMaps and Gaia GPS are updating their data.
For some applications this can take several months.