It is good to see you're well in tune with your body. That's a plus.

The indications are that you have AF, or perhaps it's really another arrhythmia, but we should probably agree that it's at least an undefined and paroxysmal tachyarrhythmia....agreed?

So far, it isn't urgent, and I urge you to try to keep calm, maybe dial the physical effort and duration back a notch, and keep a sharp eye on your hourly rate for the next few weeks. Record instances, and if your device can download an ECG graphic/record to your tablet/PC, then do that every single time you are advised that you have had an arrhythmia. Take those in hand to your next cardio visit. If she dismisses them, run, don't walk, to another cardiologist. Again, if there are P waves, it isn't AF. If the R-to-R intervals are very close to even across many beats, it isn't AF. If a few beats seem to be missing, it's PACs (premature atrial complexes, and everyone has them. They only become a problem when they run up to 5/6 at a time and come more than three or four times each day. When their total burden is upwards of 1/5%, the latest research says to start dealing with them).
https://pmc.ncbi.nlm.nih.gov/articles/PMC8190115/
About your CHA2DS2-VASc score, I don't doubt your self-assessment, but the fact is that IF...IF...you do indeed have a tachyarrhythmia, and if it is AF, your risk of stroke from an 'unrinsed' left atrial appendage (LAA) rises six-fold. Twenty percent of all seniors' strokes can be attributed to fibrillation or flutter. You always have the trump card to refuse to take a DOAC, even at half-dose, but I have just resigned myself to taking them. I sit a lot at the PC (no kidding!), and I have a history of AF, even if it is nicely in remission....for now. I have incipient hypertension, although my Galaxy watch, calibrated every 28 days, sez no. So, my risk may be high enough that I just lump it and swallow 5mg BID.