All of the new syntax is technically optional, but at least some percentage of it just makes it easier for newer/less-experienced devs to write things: e.g. classes as simplified syntactic sugar around prototype-based inheritance models, or function parameter spread operators to make learning how to arguments.whatever unnecessary and generally make code for dynamic argument lengths easier to understand.

No matter when you started learning Javascript there would have been parts too complex or obscure to learn immediately (the prototype-based inheritance model is something I think a lot of full-time professional JS devs don't fully grok). There was always things you learn first and things you learn later. With the new syntax, I think now the things* you learn first are just more likely to be immediately useful.

* where "things" excludes learning how to master every trending new library—that is a part of Javascript that isn't improving unfortunately.