In the meantime until the Garmin Connect integration is released, I've been using a self-written tool (https://github.com/jat255/fit_file_uploader) to automatically process the FIT files produced by TPVirtual and upload them to my Garmin Connect account using some third-party library tools.

One limitation (see https://github.com/jat255/fit_file_uploader/pull/13#issuecomment-2573526582) is that there's no way to access the name assigned to an activity by TPVirtual.

Examining the FIT file specification, it doesn't look to me like there's a standardized place to put an activity title, but perhaps a "developer data field" could be used for this (https://developer.garmin.com/fit/cookbook/developer-data/), instead? Either way, it would be nice to have some sort of user-friendly identifier inside the FIT file itself.