Yeenoghu is savagery incarnate. He divides all things into two categories, predators and prey, and he is the alpha predator. He has no love for the trappings of civilization, and his perfect world is one in which everything succumbs to its bestial nature. He seems like a boring, one-note monster, but oh wait we already did this.
Yeenoghu is what you get if you start with Baphomet and take away everything that makes him interesting. There’s no cunning behind his actions, just mindless destruction. There’s no subtlety in his worldview, just malice. There’s no interesting race associated with him, just near-mindless creatures for PCs to kill without thinking. Everything about him is somehow both effortless and tedious, and I see no way to turn such a basic, tired concept into a worthwhile element in a campaign. If you really like Yeenoghu, re-read the Baphomet post but substitute “gnoll” for “minotaur” and take out anything that suggests he has any sort of patience or cognition. I’m instead using this time to talk about a demon lord from a previous edition who I think deserved to be in 5E more than Yeenoghu did: