Vitamin D is associated with good things (like your team won the Superbowl) but taking Vitamin D doesn't seem to lead to good outcomes any more than taking Vitamin D will make your team win the Superbowl.
The only thing that seems pretty much settled is that when it comes to covid (and many other things) vitamin D is useless for those who are not deficient, and taking massive doses is likely to do more harm than good. The uncertainty is whether reasonable supplementation to compensate for what is a common deficit during winter is effective or not against covid, both in term or infection and severity.