There are few reasons which can explain synch problems with Garmin :
in the Kiplin app, click on your name (top right corner of the homepage) and check if Garmin connect is set up as your tracker.
Explore the other reasons by clicking on the link below and check what actions you might need to do.
Does your watch display 0 steps? It may be that activity tracking is deactivated on your watch. This tracking is necessary so that the watch can record your daily steps. The activation procedure depends on the model of watch you have.
https://www8.garmin.com/manuals/webhelp/fenix6-6ssport/EN-US/GUID-EF7A4EF4-CA4D-4BAA-ADE2-D7224D876310.html