I am not as experienced as you, but had the chance to play in a league with a similar player.

my opponent was playing Hard Defending with DL,DC,DC,DC,DR, DMR, MC,MC,ST,ST. Seems like a legal formation and always winning 1-0 and sitting top of the league
The way to beat him was to play Hard Attacking and I won 5-1 and 3-0 even when my overall quality was about 3 points lower than him

It could be worth a try