https://overthecap.com/player/kenny-clark/4739
They pushed a big chunk of it into a void year, so some of that money won't hit until the year after his contract expires.
He does have a big cap hit, but not 40M. It's what happens when you play well enough to make it to your last year of your contract. Ask Aaron Jones about that.
I could see them doing an extension and play some games with the money, but I'd be leery of it. We've seen 3rd contracts not work out so well in the past (see: Bakhtiari, David). Outside of QB, I'm not sure a 3rd contract is a good idea (unless it's a series of 1 year deals), usually the player is too expensive and too old to make it worthwhile.