Honestly, it sounds like you need a more responsive cardiologist. Mine likes to do different tests because, in his words, "we like to have as many data points as possible." I've been on a statin for almost a year, but he still would like to do a stress test. Also, he explains things.

My cardiologist pointed out to me that I entered SVT when my heart rate was near its theoretical maximum for my age. He was able to show me on the readout for a nuclear stress test on a treadmill (known widely as a MIBI test in Canada). I was advised to not let my HR rise above 120 BPM during any activity.
That was prior to a catheter ablation which fixed my AF....or rather, blocked it from happening (which is all ablation does. It does not 'cure' AF, no matter who tells you that, pro or not). Now, I routinely go on aggressive walks with some running to keep my HR elevated a bit, say in the 130 range. However, part of my walk includes a rising path on an oceanside bluff with over 300 regular risers, steps....as in 'stairs'. By the time I get to the 'Goose Spit' steps, which are on a spit of sand in the local ocean, I have been walk/running for approximately 4 km, or 2.8 miles. Then, when I take my HR about halfway up the first of two flights of steps, it shows between 140-144. I maintain this for the next five minutes until I top out at the level again. I am 73, so that HR is right at my max. I never have so much as a blip all that time. In fact, I am more likely to have a short triplet of tachycardia seated at my computer on any one day, exercise or not. But I can crest that long rise, as steep as it is (13-22% grade) and only be breathing heavily. I don't need to pause, there is no pain, no apparent ectopy, just a pounding heart, which is all I ever had in my running 'career' over four decades, including footraces.
Further, when I complained to my cardiologist, about six months after being diagnosed with AF and about five months into taking metoprolol and 20 mg of atorvastatin, plus of course the Eliquis, he replied that nothing I was taking should have affected my level of energy, and he added that he would rather I not lose my level of fitness. So, to keep running.
If you'd like to hear some advice, apart from doing as your cardiologist suggests or prescribes, it would be to play at running as you would like and see how it works. Your heart will squawk if it doesn't like it. Also, monitor your chest sensations, be in tune with your heart, and take several ECGs via a Kardia or smart watch each day. I think you may find that, unless running IS the problem that makes your heart cranky, there's something else going on. It might be mitral valve prolapse, age-related deposits of collagen and fibrosis in the atrial substrate (pretty much everyone gets at least some of this), poor ejection fraction....cardiomyopathy of some kind....I'm just saying that running may not be it. It could even be sleep apnea. That is what set me off, to my great surprise. Severe obstructive sleep apnea, found only during an over night stay in a sleep lab. It was the very last test my cardiologist prescribed for me after all the other tests, including the treadmill test with contrast dye and CT scan.

Get an electrophysiologist. I would do it soon.