Why is my mob farm not working?

https://preview.redd.it/co9j8mp9gypd1.png?width=1920&format=png&auto=webp&s=85350798b347ca547d3a5f92470cfec55991bde1

https://preview.redd.it/26arm1ybgypd1.png?width=1920&format=png&auto=webp&s=5e76577ea6f836a9d9766442e5e2e3f9a650ca8b

https://preview.redd.it/zt9is1qdgypd1.png?width=1920&format=png&auto=webp&s=a838e2bf5a180680c70b5f19511544367860c449

Here is the information: The base of the farm is at y=110, ground level is at y=60, the AFK platform is exactly 30 blocks away, the room has a light level of 0, the carpets are there to avoid spiders, the surrounding ground area is moderately lit up. (The area is not lit up its just a fullbright resource pack). All theses things should warrant a decent flow of mobs but I'm getting absolutely nothing. I've tried to listen of caves underground to see if that's taking priority however I couldn't hear anything. Please help.