How to grab BPM data from my Fenix 7 in TACX Cycling App?

I connected in GARMIN TACX Cycling App via my GARMIN Connect App credentials. It worked fine but I did not manage to connect (or include) my Fenix 7 in the cycling App, in order to record bpm data. And when I simultaneously start an indoor bike activity on my Fenix 7, then the activity is duplicated in Garmin Connect (one from TACX Neo 2 and a duplicate from Fenix 7).

How can I merge them?

Or how can I have the Fenix 7 BPM data included by the TACX Cycling App?

Many thanks in advance.