Activities can be seen at my instinct solar but aren’t visible on the Garmin Connect App
If you can't see your new activities in Garmin Connect Web with the link I posted (https://connect.garmin.com/modern/activities) then there is a sync problem and that is why you don't see your data in My Day.
Try syncing with Garmin Express on a computer.
There is a recent bug not showing activities not having any name, on the MyDay screen. Access the activity through the News Feed, Calendar, or through Activities, and edit the name. Also change the setting for the default activity name to something else than "Untitled" - see the setting at https://connect.garmin.com/modern/settings
Also check out the top, pinned thread in this subforum, for more details: Garmin Connect Mobile iOS - Mobile Apps & Web - Garmin Forums