We'll have to wait..
It's a bit of a shame that we're getting more information about OD than Physint. Although I think Kojipro was a bit hasty when they announced the game SO EARLY.
It was 2024. They originally planned to start casting that same year, but they were thwarted by a long-lasting strike that also disrupted OD filming. Even at the time of the initial announcement, Kojima expressed the opinion that they would begin Physint development in earnest after the release of DS2, but it seems the plans were changed due to the SAG strike aftermath, as it pushed Physint casting and OD filming back to 2026. The schedule has essentially shifted two years, and Physint is still in the scanning phase.
Apparently, the game is still very early in development. I don't think we'll get a teaser trailer until 2027, but I'd like to be wrong.
I've always wondered if Kojima would ever make a new MGS-style game, and overall, I didn't expect him to. He's already said he was very tired of being stuck on one franchise back then, and he was probably even glad to be freed from that. It's interesting that he finally decided to make concessions to the fans and create such a game; it will be interesting