Yea, I mentioned the study in the first link in the article, which found positive results but with a smaller sample size. The second link is the study by Nogues et al., which is not randomized. Indeed, this preprint has created a lot of confusion, which resulted in its removal from pre-print servers: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3771318#references-widget

Your point on calcifediol vs vitamin d3 is a good point, which I missed in the article. So, thank you for pointing that out. :))