Definitely, yes. You can quit the job. Because, you stated that you're working on freelance projects. Meanwhile, you can take advantage for further steps. If you do both "job" and "freelance" projects then you'll not be able to learn new stack. But if you do the job and not the freelance projects and you want to learn further, then you'll not get enough time to catch up.
I have also quit the job and now learning node.js and some other stuffs to become a good backend developer. I hope to catch better job opportunity later and gain the losses I would have.