I had no cardiovascular problems and exercised regularly running, climbing stairs, burpees, bicycling, etc for many years. A Dr found I had an irregular ECG around age 75 but I didn't think I had any heart problems so I didn't follow up with a cardiologist. Around age 80 I was diagnosed with afib and it has gotten steadily worse till now at age 85. Exercise is a trigger for me and I haven't been doing much strenuous activity at all lately. I do not purposely exercise; only gardening, and walking or biking short distances. My cardiologist and electrophysiologist recommend that I do not take an ablation risk because I do not have any symptoms like fainting, dizziness, etc. I believe that paying attention to your lifestyle and symptoms as the disease progresses and adapting accordingly will work. Everyone has different health conditions, symptoms and lifestyles, so the best solutions are varied accordingly.

I have afib frequently; the last two afib occurances were about 4-5 days/episode with a 3-4 day break with no afib between episodes. I am now thinking I can live with continuous afib if it happens; before I tried hard to avoid afib and rested a lot when in afib, but not so much now. Find good honest doctors which are interested in solving your problems, not making more money. I do take many supplements including magnesium and potassium and blood thinning supplements. I also take 2.5 mg eliquis, and 1/2 adult aspirin when in afib.
Some research on extreme exercise and afib:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818379/
https://www.google.com/search?q=afib+caused+by+extreme+exercise&rlz=1C1CHBF_enUS770US770&oq=afib+caused+by+extreme+exercise&aqs=chrome..69i57j33.16432j0j7&sourceid=chrome&ie=UTF-8