In regards to front-end skills, I'm kinda stuck on where I can improve next. I find myself dissecting libraries and building them myself with some tweaks and improvements. To me, it all just feels it's just a matter of time instead of actual skill. The same applies to learning a new technology or new design patterns or concepts, everything becomes a matter of time and I can't feel motivated knowing eventually I will get there.
I explore different kinds of frontend. Each type of frontend provides unique challenges and constraints. Consider making a frontend for:
You can also try different kinds of website frontends
You can also try changing subject matter. Frontend design for a website is going to depend on the subject matter.
You can also change the interface technologies.
Best of all, you could combine a change in all of the above areas. Make a mobile app for a geocaching video game that is about food, etc.
What gets me going is when I see stuff and I have no clue how this is done. Then I start to explore how I would go about creating something like this. Usually this results in discovering that this requires a technology I am not yet familiar with and if this is a cool thing, I pursue it.
Always ask yourself two questions: Why do you do this? What do you want to do tomorrow / Who do you want to be? There always should be a real reason of whatever you do. Is it needed for a job, for someone else to solve real problem? Will it bring you or someone else more money? If you can't answer those questions, then something is wrong. You should do something for purpose, not just in sake of doing it for fun. Fun is something you always will "ignite" and "reignite" time to times, so it's absolutely normal. You can also try investing your time into something different like traveling, writing, camping, martial arts, whatever. Try as much as you can, life is too short.
Time is core part of skill. You practice, and practice again and again. After all, you should know what exactly are you focusing on, what exactly do you want to achieve. If you have no clear vision, you will never be there. Always set up goals, plan how to reach them, and start.
Finally, fronted and web today is everywhere, you see WebAssembly, WebVR, WebGL, modern games or interactive programs like audio/video editors right in the browser, AI and ML in web, voice recognition, NLP, whatever. When I started, nothing of this existed. You have so many choices and opportunities today. Just answer the damn question - Why?
The best way to motivate yourself is Memento Mori.