Kinda stuck at 1 place!!

I cracked an internship 7months ago and currently working as part-time employee as frontend developer in that company. I want to get into fullstack or backend but can't leave a company because they are paying well and their backend stack way different + they are in need of frontend developer.

I'm at the early stage of my career & I believe I should to explore, but I think no company will pay me well as this does, so I prioritize money or explore backend? would like know your views on this. thanks