Yes, I am fully vaxed and boosted also and am really suffering with Post Covid stuff anyway.
My heart rate goes up quite easily now also. I already have some valve issues as well, but I was doing well before Covid.
I had cardio ablation for Afib about 7 years ago and that was quite successful.

Is the fatigue caused by cardio issues? Will this subside with time? Hopefully I can get some advice and honest answers from the Long Covid Clinic practitioners. So far, my cardio practitioner doesn't seem very interested. In general, medical establishment doesn't seem very interested.
I am glad that you have seen a little improvement. The past week has been basically a nightmare of fatigue and depression. Maybe one day I will get better!