It may not be _marketable_, and the value of it may not be immediately obvious, but I guarantee you you'll use what you learned sooner or later.

It seems you also skipped over what I said about being able to write code without unnecessary complexity the first time. This is _the_ skill for a programmer. Literally the only skill. If you can't do that in any language/technology, you can add a bunch of new technologies to your stack and you'll also be crap at them. Whereas if you develop that in one technology, you will know what the road there should sort of look like and what success feels like, and you won't be satisfied writing junk code while you learn. You'll pore through docs and find the nuggets that matter and set the rest aside for later. You'll read through the opinions of thought leaders and will be able to judge their thoughts on the merits, not based on their fancy title at a FANG company, so that your code will last.