Look for the player value.
My 6* player with now 36Q 20 years has a value of 4.2M, that means that your player is a slow trainer and with the level up he tend to play worst, because he will face better players.
The other one seems good, try to put him on the other side or just alone.
My best striker scores a lot of goals whend he plays with 1 or 2 more strikers, and do a lot of assists, but If he plays alone in front, he has always bad results.