He belittles me every damn step of the way. It's even hard to have a generic conversation now. If he sees me happy or right, he gets so critical or has to ruin the mood somehow.. He's neither moving forward (he's always busy in something but got time for random shits) nor breaking up! I'm tired.
You should take charge and break up
You can try to have an honest conversation with him about how he makes you feel recently.
If he hasn't been like this always then either he has been playing a character so far which he isn't able to play anymore or he is going through something bad & unable to vent.
To determine if it's the latter case or not, you can try having an honest convo with him or can think if his behaviour has changed with others as well or not.
If it is the former case and if it doesn't work you anymore; then unfortunately the only option I see is that you can say that it's not working for you and break up.
you seem like a good guy, find another boyfriend
Narcissist behaviour. Leave him. Simple.