The Dungeon Master has a lot on the plate- rules lawyer, story teller, motivator, and facilitator, there is a ton of soft and hard skills that go into being a DM.
Avoiding burnout if KEY, and one of the main ways to prevent burnout is to remember that you- the DM are also a player in the game.
You need to be a bit selfish and make sure that you are also having fun in the game.
For some this comes through world building, or throwing challenging encounters at the players.
For others it is being a part of the story through the use of NPCs- non-player characters.
Using and playing NPC’s is a great way to actually *play* in the game, be a part of the story, while continuing to be the DM.
When I create an NPC there is the usual character sheet and items that get filled out, along with a bio & backstory- how do they fit in the game and what is the motivation? From here once they enter the actual adventure, I use that as a template to see how they behave and act, getting a chance to *play* them in the game.