I have a better idea for you.
last day of the season, sell your high-rated players, make your team a 3* team, wait until the league is on, you will be with 3* teams, then buy high-rated players.
I did this 2 seasons ago. I always had a 5* team and all the opponents I played with in the cup were 1 or 2 levels above me, with higher rates. When i did this step, dropping my team to 3*, all my opponents in the cup were weaker.