Exercising with a mildly dilated aortic root

I am a 58 year old male who had my first known episode of Afib yesterday. Cardioversion didn't work so they admitted me and performed an echocardiogram and stress test. I went into normal sinus rhythm on my own the next morning. Stress test fine. Echo showed mitral valve prolapse, some regurgitation in valves, normal ascending aorta size, mild dilation of the aortic root of 4.3cm. I am 6' and 220 lb. I like to do HIIT and the big lifts, but not necessarily heavy weight (but do isometrics like pull ups and pushups). Definitely lifts requiring valsalva though. I also run hard. It is what I do to keep my mental health balanced as a vet with service related mental health issues. I was floored when the cardiologist informed me that he considered it an aneurysm of the root and that hard exercise like lifting and running is not in my future. I am devastated. I am trying to balance research with suspending judgement and waiting for a follow up with my VA doc and likely a cardiology consult. I am uplifted by what I see here. I am also dealing with an aggressive pituitary adenoma and possible prostate cancer so this is hitting me extra hard.