Here's another note from another old person (lol). I too have various arrhythmias (PAC's. PVC's, atrial tachycardia). I've had them for as long as I can remember. Yes, that makes it easy for me to accept and live with them.
Putting that aside, I think I've lived a pretty full and active life in spite of these goofy rhythms. I've lived all over the country, enjoy plane rides (even did an open bi-plane ride for one of our anniversaries), gave birth to 3 kids and raised them (if that isn't a challenge...) and I've been working with wildlife for over 18 years. Wrestling an angry raccoon, lifting a 40 lb beaver, chasing down an injured eagle - that all takes energy and exertion but I do it. My heart may act up but it doesn't stop me because I know my arrhythmias are harmless, just annoying.
So do keep track of your heart health with proper check ups, diet and exercise but then go out and enjoy life. There's so much to do.
I respond mostly to give you a quick check that people do read posts and do care. Unfortunately I don't have any new information or analysis...but can try to suggest some possible tools/methods.
It may help if you can focus on a project that will build your self confidence. This should be reinforced by the facts of your medical studies which I read to say your heart is structurally healthy - with some electrical anomalies. Here's one that come to mine based on your short post: Work with focus on losing the "extra" 25kgs you have gained in recent times, and take each lost kgs as a reason to celebrate and to feel "good" about. Try to find other thing you can "control" that you can focus on and derive more anxiety relief.
To this add a plan to diagnose and treat any heart rhythm problems that are giving serious problems. You are still young, you must get these problems under control.
That said, many of us, even some your age and younger, have simply learned to live with some heart rhythm difficulties. In my case, an old guy, I live with permanent atrial fibrillation, and while it make my heart/lung system less efficient, I am still able to exercise doing walks and light bike rides. No more running (I ran up to the age of 67, so I'm not complaining) or power bike riding, but I am still very mobile.