If I lived in a condo, with no easy way to do an outdoor chain cleaning, I would do this (which is what I do to clean the chain on my old bike that stays in the basement on the trainer for riding on Zwift):
Buy one of the chain cleaning tools, like
this one. Go to a big box store, or online, and buy a cheap gallon jug of Simple Green. While you are out there buy a new toothbrush. Find a rag, place under bike chain.
Put the new toothbrush near your toothpaste, take the old toothbrush and dip in Simple Green and clean jockey wheels, cassette and chain rings.
Fill the chain cleaner with Simple Green, clean the chain. Dump the dirty Simple Green, fill chain cleaner with water - clean the chain again, to remove the degreaser. Dry chain off with the rag.
Oil chain. Done, no mess indoors.
Agree with the other comments about the other issues with the drive train.