Identify your use: finishing crumble (salads/pasta), baking (pizza/pie), or spreading (sandwiches).
Choose the closest behavior: crumble-like dryness (ricotta salata, halloumi), tangy cream (goat cheese), or mild crumb (queso fresco).
Apply the listed ratio. If the substitute is wetter (cottage cheese, queso fresco), drain or pat dry first to prevent watery pooling.
If your swap tastes less briny than feta, add a tiny pinch of salt and a brief lemon zest/squeeze to restore the “bright tang.”
For best texture in hot dishes, add the substitute at the end (or quick-sear halloumi first) so it doesn’t turn rubbery or gummy.