Stick with something for a while 🤖
As much as you probably want to take that new framework or library out for a spin. It might not be advisable. If you are still getting acclimated with core language skills, you should probably just stick with that path for the moment. Only once you are completely comfortable, and at least moderately proficient with your core language of choice, should you consider venturing out and kicking some tires.
It has everything to do with being good at the established, while still being able to learn the up and coming
Nothing ventured... 👾
It's a fast paced tech environment and it is not slowing down anytime soon. But the truth is, employers and even freelance customers, often prefer a developer that is confident in even just a handful of technologies, over a developer that boasts knowledge of 40 different platforms and languages. Still, that's not to say you shouldn't be open to new frameworks and new ways of doing things. Libraries like React have fundamentally and forever changed the way development gets done. So never venturing outside your vanilla boxes is probably not advisable either.
So what's a dev to do? 💻
In my opinion, like so many other things, it is about finding a balance of what works for you with regards to your specific abilities. Can you manage multiple and simultaneous learning paths that include new technologies/concepts, while still being able to demonstrate proficiency in each path? That's cool - you do you. But if not, that's okay too. Don't ever feel like you need to pick up every new thing the moment it comes out. Keep to your core fundamentals and work/study habits. Find a framework, language. or library you love to code in, and just code. The more you make the better off you'll be, regardless of what new pasta sticks to the wall tomorrow.