These are the general scopes of play as I see it, pick the one you like the best and play.
Basic: At its most basic level, 5th edition is a fairly simple game, the only allowed rules are those presented in the free downloadable basic PDF. Only 4 classes and 4 races are allowed along with a very narrow field of additional background crunch. Characters are easy to roll up and virtually all of depth is provided by the players.
Intermediary: This type of game uses only the core three hardbound books. There are 9 races and 12 classes available, along with several customization options for each class. Character generation is more difficult and the different niches can be filled in interesting ways by a couple of different classes.
High: This game includes, in addition to the core books, the Players Companion, the Sword Coast Adventurer’s Guide and Volo’s Guide to Monsters. Basically everything published by Wizards of the Coast as a D&D supplement is fair game, including Unearthed Arcana articles. The options available to players and DM’s is mind boggling. The first two levels are static and never change, at this level, something new is available every couple of months. The only things not allowed are rules produced by 3rd parties.
Very High: This is where things go nuclear. This type of game can include virtually anything available from the DM’s Guild. All manner of classes and races are available and I doubt any group could or would even want to allow all of it, but it is in the realm of possibility. Niches are almost non existent at this level as virtually any class can fill any niche with just a little customization. DM’s have to be very careful at this level as to not allow anything unbalancing or disruptive to play. Of course at this level, it probably does not matter if something is unbalancing or disruptive, because everyone will have access to things that are unbalancing or disruptive. The problem with this level of play is, it is difficult to move characters from one campaign to another.