iPhone X (iOS14.4) Battery Problems

Hi

For a while now I've been experiencing problems with my iPhone X's battery.

In the beginning it would die at 20/30 percent. Now it's consistently dying at around 50 percent. I plug it in straight away and the device powers back on BUT on the battery percentage is suddenly very low - say 10 percent.

The battery percentage level also won't change for hours, and then suddenly starts dropping within a very short space of time...

I check the Battery Health section in Settings and it says 'Service' - when I click this a message appears saying the battery's health is significantly degraded and advising a replacement. This is despite the battery's Maximum Capacity showing as 83 percent. Correct me if I'm wrong but this is hardly an acceptable level to warrant a battery replacement.

I've updated to the latest iOS, done a hard reset and reset all settings. Nothing has worked so I'd appreciate any help I can possibly get with this, it's extremely frustrating and preventing me from using my iPhone outside the house.

Thank you