In terms of statistical evidence for vitamins

I only linked you vitamin D. Look at Zinc. Look at Vitamin D + Zinc + Vitamin C together (which is what the data suggests is optimal). I linked you a start to the evidence chain, not the end.

But tachycardia, heart murmurs, POTS, etc. are issues from the disease itself as well as the neuroinflammation it leaves behind

I agree the data supports that the S-protein attacks these tissues, but the data also supports the protective qualities of Vitamin D + Zinc for exactly these tissues for the exact same reason (ACE-2 receptor -- S-protein interation/shutdown/vitamin attributed upregulation).