Well, it's fair to assume that FromSoft will continue making PS exclusives as they and Kadokawa always did since the first PS.
But Sony making a deal with Kadokawa to help bring Kadokawa IPs to a global market of gaming and anime, or Sony making a minority investment on FromSoft, or this report don't secure that. I'd say that in any case what it secures is that their games will continue to be released on PS.
Sony owning a small portion of Kadokawa and FromSoft means that Sony will get a small part of the profits produced by Kadokawa and FromSoft. So the more profit they make, the better for Sony. Elden Ring made a lot of profit being multiplatform, and would have made way less if it would have been exclusive.
It shouldn't surprise you, it's very common to see Japanese (or from USA or EU) partnering with Chinese companies like Tencent or Netease. The typical case being that the Chinese company invests on the non-Chinese company and helps them to publish their games in China, or making mobile gaming adaptations of their IPs, or to make special versions of the games for China.
As an example, Microsoft made a deal with Netease for Minecraft China Edition, or Blizzard also had a deal with them, or in the case of Sony, Bungie got an investment and deal with them for mobile games. There are tons of examples.