iPhone losing insane amount of charge over night

I’m not sure what’s been going on but as the title says, my iPhone 13 has been losing charge overnight and I have no idea why. Last night it lost over 20% charge! I keep my phone on airplane mode over night so it shouldn’t be losing charge and it says I have no apps using significant energy so I have no idea what’s going on. This only started happening recently. My battery healthy is still at 96%. Does anyone have a solution or know why this could be happening??