Battery capacity

So i have the battery monitor widget app, and it shows that calibrated capacity is around 2600 mAh, so this means the battery has degraded, right?
I have been searching for original batteries, but on AliExp**** there seem to be only batteries from around 2014, and some people say the battery swells after use etc., so i'm hesitant to buy from there. Any other sites maybe?

Battery capacity max

Guys is this normal .. in file explorer ...Root/efs/battery/batt_capacity_max ... it is only 990 .. i want somebody to check if it is the same as mine .. running audax rom..