Winning the grip battle from guard is incredibly important because you get your preferred grip then you can attack and your opponent can’t pass your guard. In this drill from https://www.grapplearts.com/gripfighting (The Gripfighting and Kuzushi Formula) Rob Biernacki teaches and then demonstrates the ‘Engagement Phase Game’ (starting at 3:27). This drill is taxing but will take your gripfighting abilities to the next level.