I'm no game developer, but I'd say don't create an engine if what you want to do is build a game. Do create an engine if you want to create an engine though.

But yeah, it is like learning a new language. But that's not a bad thing! I found messing around / following some tutorials for e.g. pico-8 to be both liberating (two characters are enough for a variable name) and educative (using functions like min/max to the fullest)

[0] https://www.lexaloffle.com/pico-8.php