I had a check at his stats, and Casemiro attempted even more long balls in his RM days, and with much better accuracy. PL is just different intensity though, and its a much different ask having Kroos next to you.
We are using Casemiro as our "connector" between our defense and attack(in our 3-1-6 or 3-2-5), and him being hounded by 2-3 players didnt help, even Mainoo who is much better on the ball struggled.
This is a system issue, we need to keep the likes of Casemiro/Ugarte higher up the pitch during buildup, and use Mainoo/Eriksen along with a fullback in our 3-2 buildup shape. Ten Hag did something similar with Collyer yesterday, pushing him up. We cannot have any weak links in our buildup, players who can be targeted.