How can I beat this strategy?

Coastal, Death Match

Opponent will be britons (his only skills are eco, turtling castles (so many castles) defended by infantry and longbowmen with a cavalier counter, defending the one narrow passage with cannon galleons, galleons and castles, walls, towers)

Can I beat him? I lost when we were britons vs. britons but we’re having a rematch. We do 20min treaty so I might just focus on taking the passage before he can? But then he’ll destroy me with cannon galleys...