HELP: Random FPS drops

I have recently had problems with DOOM 2016 regarding sudden FPS drops. In VEGA Core Processing, or whatever, when I look at certain areas, my FPS goes down from 60 (VSync) to 35-40, and it's driving me insane. I tried searching Google, found nothing, I tried asking the Steam community, unsurprisingly unhelpful.

The thing is, this NEVER happened before, and it only recently began occurring. I know it's not a specs problem, because again, it worked just fine a few days ago.

I'm using the Vulkan API, with VSync turned on. I do not have Razor Chroma enabled, and my resolution is 720p.

I have no pending Windows Updates or driver updates. What I want is some kind of console command that could possibly be the culprit. I have the DoomLegacy Mod, which expands the list of cmds and cvars. HELP. ME. PLEASE.