iPhone 8 not charging past 80% after battery replacement

The macimum capacity of my iPhone battery dropped to 86% so i decided to have it replaced (not by Apple). With the new battery, it wouldnt charge past 80% unless i leave it on charge overnight ( optimised charging was turned on). I turned optimised charging off and it still wouldnt charge past 80% during the day. I took it back to where the battery was replaced and they change the battery. The problem still remained.

I took it back and they put my old battery back in. Now the old battery will not charge past 80% unless i less it on charge overnight.

If anyone can help me with this please let me know.