Agreed. I think Death Stranding will give his studio additional clout and he'll start making projects based on available deals plus the occasional Sony one.
I think he will stay partnered with Sony exclusively and eventually they will acquire Kojima Productions. He hasn't gotten his big payout yet and he will likely cash in at some point just like Ted Price did.
I feel like the Decima engine is a big anchor keeping Kojima Productions tied to Sony for the foreseeable future. Kojima Pro has done a lot of working and tweaking on engine to get it working just how they want, collaboration has been so significant they even renamed the engine to reflect the Dutch-Japanese link.
Can't imagine Kojima Productions wanting to disregard all that after just 1 game and start from scratch again especially given how much Kojima disliked when it happened the last time.
He also wants to continue DS after this first game. As long as it doesn't bomb the partnership will probably grow stronger.