IS THERE A WAT TO GET RID OF THE RATS, ROACHES, AND LEAKING PIPES WITHOUT MODS?

You can remove those things with cheats so that they disappear forever. Unfortunately you might need the all cheats mod by TwistedMexi. When you are in the apartment in live mode, pause and enter Ctrl + Shift + C. Then type testingcheats true. Then shift click on for example the rat hole and select delete object. The rat hole will be gone forever, this also works with bad smells, roaches etc. it's a bit tricky to shift click on bad smells and roaches to remove it but it is possible.