I know it sounds like a meme, but just listen.
try mindfulness/self awareness.
at whatever point you can in the process, stop for even a split second and ask yourself, "why am I masturbating right now?" or "why do I want to masturbate right now?"
just work at that for a while and try to pay attention and actually come up with a reason or two. even if it doesn't stop you then and there. just keep doing it every time.
it seems like you don't have much going on in your life. if you really made it, think of the money as a utility. it is merely a tool. it won't bring you happiness in, and of, itself but can give you easier access to things that make you happy.
short term, start getting out of the house, even if it hurts. do whatever you can, but push yourself. get some sun, some fresh air, take a multivitamin, eat some veggies, eat regular meals. take some damn interest in your life. treat it like your own personal experiment if you want.
use your money to develop some hobbies, preferably outdoors or athletic, but something craft focused can also be good. from there starting reaching out and building connections, there are lost of IRL communities built around hobbies, you'd be surprised. online groups are great for general info but irl groups are much better.
once you have some of your life sorted out, look into moving out of the house, now that you can actually take care of yourself, and maybe even enjoy it at times. this will give you a huge sense of freedom and living with parents as an adult really feels shitty, like you're trapped by your circumstances.
try turning one of your hobbies into a small business. if you have the money it makes it easier. maybe if you make a couple good friends in one of the hobby groups, propose setting up something small that requires minimum effort on their part so that they can stick to what they like doing.
also, read books (on stoicism), reduce screen time, maybe try an elimination diet? also, go to a doctor