In my experience, i you still have 2* players, sell them imediatly, with only 1star, no body buy them, and you have to put them again with 2 stars to sell.
Most of the Team are abandoned or boot robot, it is a good opportunity to renovate your Team.
Go for the players with cost about 3M with 5 stars, or 1,5M or higher with 3 stars, i didnt find good 4 stars players. If you whant to fill one position quickly look for 31 or 32 years old that cost above 900K.
Bet in the cup, since the first rounds you will find a lot of weak abandoned teams.
I started with 18 and i am near 25 at this point, still fighting with to other teams to win the league and won the cup, didnt qualifica to CL last season, so no experience in that point.