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.)
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.)