New venu 3 owner connection issues

Hi just invested in a venu 3 and am struggling to find out how to sync info with my Samsung galaxy s23. Ie steps activities etc. I have just started indoor cycling as I can't run anymore. Do I need a speed/cadence sensor? My bike trainer is bluetooth enabled but only works with iphones apparently! Is it worth upgrading to iPhone to get best out of Garmin watch? How do I access cycling activity on watch?? Thanks