IPhone X not holding charge. Goes from 100% to zero in 1 hour. Phone feels hot.

All iPhone Xs are still under warranty, so my advice would be to make an appointment with the Genius Bar at your nearest Apple Store to have your device examined and repaired.

You may also want to check the Battery Preference pane to see if it shows any apps as having an extreme amount of battery usage (and delete any that show a ridiculously huge amount) and also what the "Battery Health" pane reveals.

Genius Bar Reservation and Apple Support Options - Apple

Hi

You have a faulty battery make an appointment at Apple store or authorised apple repairer.

Cheers

Brian 🇬-1F1E7;