I would implore you to look at the link again. The first thing mentioned is a 4chan post from a "Konami employee" that proclaims Koji Igarashi is involved as producer on a reboot and that Sony wants to buy the IP. Dusk Golem has said the 4chan post is wrong, and he was one of the first people to mention how Sony was interested in working with Konami on Silent Hill.
Dusk Golem went on Twitter recently to rebuke it further.
What's real is Sony is working with Konami in regards to Silent Hill (Dusk Golem's Twitter feed talks about bounced about Silent Hill projects that never went public and names at least one studio that worked on a game after Silent Hills got cancelled). That's all that's real about this rumor. We can assume this is real because this has been
the guy leaking Resident Evil content for years. Until today, I've never even heard of Jack of All Controllers and what they've proclaimed that came to fruition. Their article, prior to the update about Sony buying those IPs, cites Rely on Horror for the Silent Hill Sony/Konami collaboration stuff, which Dusk Golem is acquaintances with. The main bulk of the article is based on the Silent Hill stuff, which is real. It even says that Sony does not wish to buy the Silent Hill IP. The stuff about Castlevania is based on a 4chan post, which says that Sony wants to buy the Silent Hill IP...do you see the contradiction?
What's going on with Castlevania, if we are to believe it's still being worked on, has nothing to do with the above. All we know is that Konami wants to "counter" Bloodstained, presumably with a Castlevania game of their own. But those were ideas they wanted to do two years ago; I'm assuming they still wish to, but for all we know, it could be cancelled. Look how long it took them to release Grimoire of Souls, and that still is out only in Canada.
Sony does not want to buy Castlevania, Metal Gear, or Silent Hill. What they're doing with Silent Hill appears to be more of a licensing arrangement, like what Sony has with Marvel and Spider-Man. The only thing we know about Castlevania is Konami wanted to "counter" Bloodstained, and that has nothing to do with this Sony rumor. Hell, the person who said a new Castlevania game was in production and named the series specifically, Vergeben, said it was a Nintendo Switch game. He confirmed that Castlevania: Requiem was a thing before that got announced too, as well as Contra: Rogue Corps.
So, to conclude here in a tl;dr
- Konami is likely working with Sony on Silent Hill
- Konami has expressed interest in the past of likely using Castlevania to compete with Bloodstained
- The only platform we've ever gotten hints a new Castlevania game would be coming for, from leakers who hold some credibility, is for the Nintendo Switch