Managed to win the cup as a level 6 player in a level 8 tournament. And I didn't change how I run my squad to make it worse at the end of last season. I did what I normally do.
At the end of last season, I purchased free agents and sold them to make some extra cash. On day 27 of last season, I sold off a few players whose contracts were expiring but were only going to be three star players this season. I purchased about 5 5* Nordeus generated players on day 1 of this season. I also purchased one scout striker (only scout ever purchased for this team) who played the cup/champions league games and not the league games. I usually played my better players in the cup games and the second team players in the league. I saved skill points on players as they approached their next star to see if the player would get a new position, special skill or move to the next star.
End result. I won the cup over a level 8 team who was almost 4 QP higher than me. (I am a low five star player on level 6) I clinched first place in the league after the games on Tuesday. And I lost in the semis of the champions league.
So, it is possible to be successful without destroying your team at the end of the season.