Hmm well what is it you dont like about your mixes? Feel free to post some here and maybe we can critique.
If you dont have monitors at all it may be worth investing…but judging by your living situation it also may not. If you have really solid open back headphones, use reference mixes, and check your mixes on many different setups and you’re still dissatisfied (we all are, buddy) I really dont think expensive monitors are gonna fix all that for you. Or tell at you that certain things are worse off. You probably already know what you can do better anyway.