3a Battery drain issue

Okay so it has been a week now since got my 3a.

At first i didn't had the original charger for it so I was charging it using a 67 W xiaomi charger with QC 3.0.

The battery was draining quite fast, i would charge it to 100 and it would be 98 in a few minutes.

So i researched a lot and bought the cmf GaN charger.

Charged with it once. The phone lasted me almost 2 days with minimal use. But the battery was still draining quickly but the backup was good.

Charged it again to full yesterday and rn it's at 10. And I played some light games, used reddit and youtube that's it.

Is this normal?

I am using the 65 W port on the cmf charger should I use the other port?

Or is my unit defective?

I mean on a full charge it wouldn't last a whole day with some music, 1080p video playback and some light gaming?