In response to the op, I would say that is a very relevant question, as I myself have always thought about that too, I did think about that before the bitcoin spot ETF was approved, everyone including myself expected that the price of bitcoin will go parabolic as soon as SEC announces that the ETF has been approved, but some time later, I paused to think or imagine what if the price of bitcoin drops after the ETF approval, how will I feel and how will most people feel?
It's a normal thing to always have this kind of feeling, and this is one of the reasons why we are advised to always invest not more than we are comfortable losing, regardless of the trust in bitcoin, investing in bitcoin still carries various degrees of risk depending on the entry price.
So, if you have invested the amount you can comfortably lose, this imagination of bitcoin price dropping after halving shouldn't bother you too much.