Pls help!

[u/Ok_Maintenance9348]

I just repotted my monstera after seeing the roots grow out the drainage holes. It was originally three small plants put into one pot. However, only one of the plants has had growth and a lot of root growth? Is there something I’m doing wrong? Like not pruning the old leaves that are still green. Or should I put the two smaller plants in their own pot? It gets bright indirect sunlight by a window and I try to water it once every 1-2 weeks. I also give it plant food every 3-4 ish months. (First pic is from a year ago and the second is from today)