Ending a route without stopping the current activity

Yes you can do this.  Make sure the routes you want to follow are saved on the device beforehand.  Navigation and activity recording are separate things.

You can stop a route and load another one while continuing the activity. However I only tested this with routes that were already on my unit - in that case you simply select the new route and continue your ride.

I don't use Connect IQ apps at all and therefore don't know about any limitations during an active activity. Instead I use Garmin's Courses Sync API to have my rides directly synced from Strava and Komoot to my Edge 530. See https://www.dcrainmaker.com/2020/05/garmin-launches-strava-komoot-route-sync-works-on-devices-a-decade-old.html

Thank you for your help. You are right indeed. The problem is when I don't have the routes saved on the device and create one on my mobile phone for example and want to send it to the unit using garmin connect app. Let's say I create a 100km route and want to cut the ride short and do something else instead .I know there is a back to start option but this will not help me in this case. I can stop the navigation but it seems that I cannot load a different route without stopping the activity. The device will not sync with a newly created route without stopping the activity.

I wanted to load a route that was not downloaded beforehand on the device itself. I was playing with the unit earlier and I can create a new route after stopping the current one but the device will sync with the new route after this has been turned off and on. I would be grateful if you could recommend a different way to load a route.

You can transfer RWGPS and Garmin Connect routes without stopping your activity using an IQ Widget like GRouteLoader

https://sites.google.com/view/grouteloader/grouteloaderiq

Nothing against said widget, but personally and frankly, I'd consider such third-party IQ widget-based workarounds which access other third-parties in order to avoid a surprising limitation of Garmin's software rather cumbersome. This should be native functionality. And if it isn't I'm willing to look elsewhere.

I've used previously a wahoo elemnt and everything was dead easy to use. I decided to get something newer and better at navigation which is able to do turn by turn and able to re-route. Even after three weeks of use in still not totally familiar with the device. The community is great but I'd rather have a great device which is easy to use. That being said, the hopefully the developers will see that there is still work to do in making this a great device.

I don't want to push you into any direction, but the Wahoo Elemnt Roam does turn by turn directions and re-routes - it's the major feature of the Roam compared to earlier Wahoo units.

Its a shame that I have to look elsewhere, i read so many good reviews about it but unfortunately this is not as good as established magazines praise it.

No it is not possible. With every firmware updates I am looking when Gramin fix it for EDGE devices. It is so common that during long ride you want upload Track created on GCM to your device from phone and still keep your activity running. But Garmin not acre about this. 

As I know it is possible with Fenix watches. So it is possible in Garmin ecosystem but for some reason Garmin is not giving this functionality for bike users