Sharing gpx routes from different Apps (Androd)

On my Samsung S9 (Android 11) with UK OS Maps and Garmin Explore installed  as Apps I was able to create a detailed route in OS Maps and the directly 'share' this to Garmin Explore  It worked well as OS Maps are far more detailed here in the UK.

I have a new Android 12 phone and have reinstalled both Apps on the same user ID. However, I have lost the ability to share a route from OSMaps to Explore. I have to create a route in my old phone and share it with Explore. I then have to sync with the main explore.garmin.com website from old phone and then sync to the new phone and finally to my Mini 2.

I know this is a UK-only interest post but is there a simple way rather than exporting and reimporting  gpx files? These no longer work on my new phone and an exported gpx  route from OS Maps only shows the waypoints and not the entire path.

Any ideas welcomed.

Dave