MARQ Golfer difference between pairing to Golf App vs Connect

Hi, I'm considering buying an MARQ golfer Carbon gen 2 available at an attractive price.

I noticed that it pairs to my Android phone using the Garmin Golf app instead of Garmin Connect.

I want to ask how Primary Wearable and Primary Training Device works in this case. 

Secondly I am already anticipating bugs/problems/glitches such as duplicate notifications between my Fenix 7X which pairs to Garmin Connect and MARQ Golfer which will pair to Garmin Golf.

In the past I had revoked notification and location access to Golf app to remove any doubts it may be interfering with WhatsApp call notifications etc.

I want to ask if anyone who is using two such watches can share their experience with me.