Help a CS newbie with sync issue/question?

Greetings all, just joined CityStrides (CS) this week. I was trying to sync all of my old Garmin data into CS but read on another forum about Garmin only allowing data to sync going back five years due to a policy change in August of this year. (Hate I missed this by a few months!) Looks like my data from the past five years has been synced, but I have data going back to about 2007 that I would love to get synced. Is there any way whatsoever to do this? Any help whatsoever would be much appreciated. Thanks for the help. Looking forward to being a part of this community.

You could make a backup of your Garmin files with

Make an account on RunKeeper an upload all your old runs.
They supoort import of multiple activities, maximum of 100 files at a time.
https://runkeeper.com/trackMultipleFileUpload?multiFileUpload=

What @hjkiddk said - export from Garmin, import into MapMyFitness/Runkeeper/Strava, then connect that to your existing CityStrides account in your settings page.

I wonder if https://tapiriik.com/ figured some way around the 5 year limit…