Safe to delete tracking account?

After Citystrides syncs with Strava and dumps the data into Citystrides, can I then delete the Strava account with Citystrides retaining all of my old Garmjn data (ie older than 5 years ago)?

I would not advise doing this.

I suspect that the account deletion in Strava will effectively send an ‘access revoked’ alert to CityStrides, which would in turn delete all that data in CityStrides.