poor charging on Pixel 6pro

When I use my phone on the charger, it charges very slowly, maybe +2% charge in 1.5 hours, I bought a used phone, it has +- 860 charging cycles. What's the matter? I have a charging unit from Xiaomi for 22.5w and the wire is 3.0A. and if you don't use the phone, it takes +- in 3 hours 40 minutes to fully charge and it's constantly heating up. What's the matter?