You can pay Apple to replace it for you, and the cost is not that high. £90 or so.

If the battery swap fails, you’ll get a as-new replacement phone and you also won’t be charged.

In exchange for this monetary cost and the inconvenience of leaving your phone at an Apple Store for 1 hour; you get peace of mind and a highly rated water/dust proof phone.

(Seriously, I’ve seen people diving with iPhones - no case - recording videos.)

I've done exactly that with my iPhone 14 Pro. Battery was degraded down to 72%, iOS suggested in the Settings app to get the battery replaced either at an Apple Store or at an authorized service center. I made an appointment at the Apple Genius Bar and took care of it in a little over an hour for $99. A lot cheaper than buying a brand new phone!