Hi Moe! In 2020 we could have certainly referred to it as, "it's been one of those years." We had the Covid pandemic and lockdowns. Businesses have gone bankrupt. Many things are unpredictable in a bad way. The phrase refers to a series of events that seem beyond one's control. When one uses the expression it often just means having a bad year. The details don't necessarily need to be described or explained. "It's been one of those years" and that describes it.

Yes it is with the same basic principle as “one of those days” but in this case it is one of those years! Great question.