A visit from Hermen is normal because as head of PS Studios he often visits the 1st party and 2nd party studios. He could visit them for any random reason.
Maybe Jimbo visited the Sony HQ for other unrelated stuff, and since it's next to KojiPro HQ he went to visit and say hi because maybe he didn't meet Kojima since before Covid. It may be the case, but Jimbo doesn't visit random studios so if did it is because values Kojima and maybe was to sign some kind of deal (maybe the DS2 deal, or signed maybe another deal like a movie or their next game after DS2) that in any cause could have signed at home. Kojima said he'd keep independent.
I think the most revealing visit is the one from the SIE marketing guys. This is not something from protocol/PR/diplomacy to keep a good relationship betwee SIE/PS Studios and Kojipro. It's a business meeting that means Kojipro is working on a marteking campaign with SIE for a Kojipro project, very likely DS2 or a movie. I assume hints probably a 2023 or early 2024 reveal.