Domain change : Is it possible??

I have been working as a frontend developer for the past 2 years. Recently I have joined a new company and for the next switch I'm planning to learn the backend too.

I have zero knowledge of JAVA but i have worked in NODE JS and have some basic knowledge of it. I know JAVA has more career opportunities but I have to start from zero for that and I'm afraid of that.

How's the Market for MERN/PERN developer? Is it worth studying? Are big tech companies hiring for NODEJS backend developer?

I am currently working in one of the public global companies and I'm hoping my next switch will also be in any of the public global companies.