I write using all my fingers, but I've never managed to attain full mastery, for example I never use the correct fingers to type numbers in the top row, or I struggle with special characters. Sure, the letters row I am comfortable (although I could be a bit better, I'm at 76wmp 96% accuracy) but the rest I'd love to be able to master them.

I searched a bit and found about Keybr, which seems really cool and it's open source. Of course MonkeyType, although that looks a better tool once you've already feel more comfortable and not to actually learn, and it's also open source. And then TypingClub, which has a nice tree that teaches you everything in order. What do you think it's the best approach? Maybe first do the TypingClub lessons, then practice every once in a while with either Keybr or MonkeyType?