Is there a manual upload an activity to a connected app rather than auto sync

Yes, but you can do it right on the watch. If you only got one service connected it doesn't matter that much, but if you connect like in my case maybe 20 services and have to delete duplicate activities everywhere it will be a pain.

8019408 said:

I thought would be simple thing for app and software developers to create rather than having to use a computer to drop files into another place which is not that straight forward,

No, it would be neither simple, nor straightforward. To understand why, you need to know how the data transfer works: When an activity is recorded and saved by the device, it is then synced to Garmin's server (to your Garmin Connect account). Garmin does not send the activities anywhere else. It does not drop them to 3rd party services. It merely has an interface (API) for the 3rd parties, where they can peek in, and pick whatever they want. Garmin controls in no way when they do it, and what they pick.

The API is common for all 3rd party services, and you can have tens of them connected. All of them have the same access.

It means if you want that Training Peaks reads activities only from your Edge, but not from the watch, you would have to ask Training Peaks, to implement the filtering feature.

There is also another option you have, if you want to keep the double recording - create two Garmin Connect accounts. One, where you add only the watch, and another one for the Edge computer. And connect only the Edge's account to Training Peaks.

Thanks for that appreciated the feedback and the help to understand why a manual upload button is not see easy.