Hey! I strongly suggest you should make a guardian farm. Start by placing the spawners in a really big circle. Place water buckets in the edges and make a really big hole in the middle. The guardians will spawn and will get killed by the fall damage. In the platform, you built where the guardians die, place water buckets in the edges and a hopper in the middle so the drops get pushed in the hopper. If you have enough money and you don't feel like placing water on the platform, buy a mob hopper chest so that the drops go instantly in the chest. That way you won't have any losses.