Uhm it's in Settings
The first item, even. But it's global across all images, not per tag (complex filtering is… complex)
On my alt account I've been using a Minumum Score of -4 since forever. Basically hidden tags keep out the worst of the stuff, and I let score filtering do the rest (untagged shitty memes etc)
It is incidentally the reason people need to lern2hide because for some artists I have to disable that threshold (read: I browse them from this account) because for some reason they attract downvotes for absolutely no reason. Like "ohey it's this artist I have spoilered INSTANT DOWNVOTE". Comments are also literally divided between "ogod not this shit again" and people that actually like the art, that one little detail, etc.