I did not get any touch-typing lesson as a kid (the Amiga 500 keyboard felt so massive...), so I developed a pretty fast 6-finger technique that helped me into my early 30s - I was considered a very quick typists in chats and the likes, but writing code was still error-prone. At one point I saw a colleague touch-typing properly, and I felt so envious that I decided to do something about it. I started doing lessons but somehow always ended up peeking. Eventually, 5 years ago, I moved to COLEMAK, and that forced me to learn proper form. I can now push 60 to 80 wpm on regular text with no effort.
I still struggle somewhat with special characters, because of my short pinkies. I am currently experimenting with alternatives (see http://blog.pythonaro.com/2020/06/better-access-to-special-c... ) but I've never been good at layer-switching and it makes me still pretty slow.