I found my Garmin smartwatch to be invaluable when I was monitoring and trying to manage a-fib. My cardiologist and his nurse seemed dubious at first, but I was able to show the elevated HR it showed was when I was in a-fib. Besides medication, I tried relaxation, mediation, exercise, sleep- but there was no correlation or mitigation.
When I would ride, there was a high probability it would trigger a-fib, particularly climbs. The Garmin, though, ironically, was useless in tracking cardio zones and raining effect because of the a-fib. I felt pretty bad about cycling and running (until I had the ablation)- when you do something that's supposed to be good for your heart and you end up with a-fib anyway.