Frustrating that this can’t be done. When I zoom out on the map I don’t want to see a single marker showing where the currently selected run was, I want to see markers showing everywhere I’ve run. This is much more likely going to motivate a holiday/work trip run if it’s in a country or area I haven’t run in before. Doesn’t feel like this would be difficult to do but it would be a very welcome addition.
You can make a map like this, but in other program, instruction here: https://forums.garmin.com/apps-software/mobile-apps-web/f/garmin-connect-web/63103/show-all-routes-on-the-same-map
the following approach works: www.musings.ch/.../ - but note that showing all tracks becomes difficult to navigate if you have many of them :)
I just ran into the same question, and this forum was on the top of the search list.. I think I found an answer to the question, so let me share here, as others might find this useful.
So for me, it was the Garmin explore app on my phone. I can't remember, whether I had to enable sync or just signed in, though it can see all my activities, and show all of them on the map.. marked with different colors, and when I click/tap to the route, it lists all the activities there. I can simply check some numbers in that app, also the date is visible, so after that it is very is to open the same activity in garmin connect.
I guess that's all :)
I hope that helps