Augmenting Your Immunity: Fighting Covid-19 (diamandis.com)

To me - this reads like a collection of home remedies, without good sources.

Some of the recommendations are good, but it's mixed with pseudoscience.

You can always spot the clickbait and pseudoscience when talking about vitamins. They always say "vitamins can boost your immune system" which is at best a half truth. If you don't lack vitamins you won't get any boost at all but that doesn't make for a good headline.