For the most advanced (well explained) Javascript and all the way to Typescript and beyond, get a FrontEnd Masters subscription for a few months. Top notch teachers in all manner of content and Kyle Simpson will lay it out well in his many videos (among other great teachers like Will Sentance). The SessionStack.com and Logrocket.com blogs cover some important concepts with modern ECMAscript standards. Surma and Jake at Google are great and have a lot of YouTube resources to bite into. Maybe start with 'What the heck is the event loop anyway?' by Philip Roberts and then Jake Archibald's: 'In The Loop' to get a foundational understanding of what is happening. Javascript.info also a great text resource. You don't know Javascript also should be on your list. Honestly there are so many resources these days including specific YouTube creators but really it's more about your learning style and what works best for you.
Highly recommend you look at JanusGraph. Gremlin query language is quite easy, it's open source and the underlying graph DB for most cloud providers. I've extensively looked at the others. Janus Graph was our choice.