Lose. Don't win all your games. Make sure you only win 17-18 and then do not win your league. Then you can spend another season down there. However, I think purposely not trying to promote when you are clearly a top team in your league is silly. It is ALWAYS better to promote even if you might struggle at the next level in my opinion. You get a big fan survey and attendance boost for the next season if you win your league and promote as well as prize money if you win your league. That money and boost next season can help you expand your arena or get better trainees, or better skilled players. Not to mention the IV leagues are much more exciting than the V leagues. Try to promote. It is worth it.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs