I went through that exact problem, I had my doubts that I would ever get faster but eventually I did.

I insisted on typing the correct way despite being slow even at work, unless I was sharing screen with someone and didn't want to seem like I can't even type lol

I also did every step of the site I mentioned, it helped very much in building the initial muscle memory. Once the muscle memory was there, I started to get faster and faster without much effort. The hardest part is achieving that initial muscle memory even if it's slow.