Apologies, this may seem "duh" to some other collectors. Are there any threads available where the "meaning" of varieties are discussed? When is a "variety" truly a variety?
I have shared these 2 websites over the years here on CoinTalk - https://www.ngccoin.com/news/article/1655/Variety-versus-Mint-Error/ And https://www.pcgs.com/news/mint-error-or-die-variety
You're asking a question that has been debated, argued, fought about by all the "experts" for as long as the two terms error and variety have existed. And it is still going on ! I doubt it will ever be resolved or any consensus ever reached.