I don't use Komoot so my answer may not be correct but if they follow the other websites that may be a paid feature. You can try this as a workaround, I had to do this a few times when RWGPS was down for maintenance and I had to use Endomondo to create my routes. If Komoot can export a .fit file, use that rather than a .gpx format. Download it to your PC and email to yourself as an attachment. In your phone, select the download and it should automatically be opened by the Elemnt app.

Since you have a Bolt, you may want to try the free version of RideWithGPS rather than Komoot for route building. Downloading a route to the Bolt is pretty much automatic and you don't have to use your PC or the companion app. They will download directly into the Bolt when the Bolt is connected to your WiFi and turned on.