Please fix battery drain issue on ios 14

Give it a few days to finish the work of the installation. the battery is busy finishing the indexing and making changes for the update. If it does not improve in a few days, make an appointment at the nearest Apple Store for an evaluation and explanation of your options.

You're not talking to Apple here. We are just users like yourself. If you are having a hardware issue contact Apple Support or make an appointment at an Apple Store.