Did you make sure and Save your changes in the visualization tab?
If I make changes to popups and symbology in the visualization tab and save it, when I add the feature service to a map, it will honor the saved settings.
However, this saves the information to the HFS, and not to a map. If you already have a map with that feature service (Survey123/FieldMaps/Etc.), changes made in the visualization tab will not be reflected as they have already been saved in the map. Re-adding the feature service to the map should load it with the saved configuration, then any 'changes/overrides' will be saved in the map, not the layer.
So, make sure you save the changes in the visualization tab, then add that HFS to a new map and see if the changes 'stick'.
In case this help,
R_