iPhone 16 charging inconsistently and battery percentage fluctuates

Hi! I'm having an issue with my iPhone 16 charging. Last night, it wouldn't consistently charge, and flipping the USB-C cable sometimes made it start charging. This morning, I tried multiple chargers, including a higher-powered charger, and restarted my phone, but the problem continued.

My phone recognizes that it's charging because the lightning bolt stays visible, but the battery percentage keeps fluctuating and sometimes drops significantly even while plugged in and not being used. For example, it dropped from around 20% to 10%, then went back up a few percentage points. My battery health is showing 90–100%.