I just finished a soccer game which is already hard for a Garmin to track, but I've never had a problem with syncing a game to the connect app. I tried manually syncing it, but the file has 0 bytes so basically it's empty. That's a bit concerning. I don't know how long I ran for (maybe 5-7??), I just know it was roughly 2+ hours of data. While I was trying to sync it to the connect app, the app gave a notice that the servers were down which might've contributed to the issue. I've also tried to repair it myself using the fit file repair tool, but cannot get it to work with my computer. I'll attach the activity file below in case someone with great ability than me can save it.
[solved]