IPhone SE charging issue

Always check your Battery Health before doing an update. Go to Settings > Battery > Battery Health and if it is below 80%, then I would recommend replacing it first. You will also see in Settings there that is says Service is required for your battery when it does drop below 80%.

Certainly a 6 year old device is likely going to have needed a battery replacement by now, it was only expected to last 500 charge cycles. Also there are many people that neglect that Service recommendation, then wonder why they are experiencing problems. Performing any update will put stress on a battery, just like using your lights at night in your car. Your battery in your car may need to be replaced and seem to work fine during the day, but once you put that extra demand on it, whether it is using the lights while the car is not running or even experience cold temperature overnight, you may find it not able to start. Of course, it is not the weather that caused your battery to fail, it just needed to be replaced earlier.

Why does charging fail on a device with a battery that is recommending service? Because heat is generated while charging and a failing battery is unable to meet the demands of the update to index the files in the background. When that happens charging stops to prevent an overheat condition.

If you battery needs replacing make sure that is done by Apple or Authorized Apple Seller. There are also many users who did not do that and have a third party battery in their phone that is performing poorly, and now they wish they didn't, but that does not stop them from posting about a failing battery and blaming their actions on something else.

Its 100 %