Are these replacement batteries actually 3500mah?

So I recently purchased and installed a replacement battery for my Samsung Galaxy s8 plus. My battery health was roughly 80% and I thought I'd go ahead and get a new one two years after buying the phone. The replacement battery that I just installed, and followed the instructions on charging and discharging, shows way less mAh then the two year old battery I just replaced! Fairly disappointed, what should I do? my old battery was supposedly still around 3000 milliamp hours this one is barely showing 2300 millamp hours. Picture attached.