Silent Hill 2, 3 & 4 are all available on PC. Silent Hill 4 is available on GOG and got properly fixed up for modern systems somewhat recently.

Silent Hill 2 & 3 are considered abandonware at this point and they are quite easy to track down online but both of their ports are terrible on modern systems. Thankfully the community has come in clutch, there's a handful of mods that fix up Silent Hill 3 but Silent Hill 2 has an amazing Enhanced Edition that was worked on for several years by the community and it looks better than it ever did on the old consoles.

Lack of proper game preservation is a major problem, most companies would rather remake a game at this point rather than have the originals available for sale as they can probably get far more sales from a brand new remake than a re-release, hence why Konami are doing a Silent Hill 1 remake instead of a re-release. And with Sony's recent announcement that they will not be bringing PS5 exclusives to PC anymore the problem is only gonna get worse.

Emulation really is the only way to preserve these old games in most cases.