My iPhone SE only boots on quick charge
The battery is dead and needs to be replaced.

If you can only power on and use your phone while it's plugged in, then the battery can no longer hold a charge.  It needs to be replaced.


Fully charged MacBook Air turns off when power cord removed
iPhone turning off on low battery


"Quick charging" has to do with the current that the charger supplies.  It's not a mode you can select.  Laptops don't have the ability to quick charge as a typical USB port only provides 5V at 500mA max.  You need at least 2.4A to quick charge (12W).

You can try doing a hard reset of the phone, but if the problem persists, it's definitely a failing/failed battery and it will need to be replaced.