unless you’re talking about the very very basics.
That’s more or less what I was saying… but even intermediate HTML5 can be learned in no more than two I believe. Think about how you code a page… the VAST majority of what we use isn’t super exotic HTML. It’s semantic markup, with a few classes and ids. That’s it. Then comes the infinitely more fun part… CSS + JS + Your backend language of choice.
In all honesty, you can be coding meaningful Python utilities in like a week. HTML5 is a 1-2 day thing for 80% of what you’ll ever use.