I had the same issue with my community (PS5) and a sister community (Playstation). My community was much more active but niche compared to the other community. Ultimately I was handed control of the sister community (PlayStation) by the former mods and both communities voted overwhelmingly to merge under the one with the larger umbrella.
I think this is something you should consider down the road. It may not be the best for now as foodporn and shittyfoodporn and recipes are all very different, but I believe lemmy is working on a flair/tagging system. When that goes live you could unify under c/food and then use tags so that users can set up the filters on their end. If someone only wants recipes, they can filter out shittyfood and foodporn. If someone only wants shittyfood, they filter the rest, etc.
Best of luck on all this. I am still working on managing the very large transition we just did. And we will be looking into mandatory flairs when the feature goes live to help those only looking for certain content.
Edit: I am subscribed to all of the food communities. I don’t do much cooking but I love the food! I’ll be sure to vote more frequently
Matrix