Resident evil is a weird series the branches into different genres over time. The first few were survival horror and played on the dread of not being well equipped enough to get through the rest of the game. Then Numbers 4-6 become action games with unreasonably sexy badass characters. They were good games, and some great co-op, but not scary at all. 7 was a horror masterpiece (or at least the first half). 8 looks like it'll continue along that trend. The recently reimagined Resident Evil 2 is phenomenal and finds an unexpected sweet spot between all 3 of them where it's still action-y, but has a bunch of things that are suspenseful and scary.

Silent Hill struggled to get out of the original playstation and hasn't had anything good in years. Remakes and remasters of the originals are generally perceived to be lower quality. I would try to grab an emulator and just play the first 4 in order then pretend the rest doesn't exist. Number 1 and 2 are the treasures of the series.