I got comfortable on the basic Vim keys using shortcutFoo [0], plus actually diving in to using it full-time. Learning Vim takes full time usage as you need to switch over your muscle memory. I still find that GVim is brilliant for beginners as it is tolerant of using other style shortcuts so you don't burn yourself. Even though you might learn slower you're more likely to progress as it's less frustrating.
I don't know if there's much evidence of these game style methods actually working. I tried vim-adventures [1], but just found it annoying. As far as I can tell you just want to apply similar learning techniques as with touch typing, so just typing the letters to the screen.
As a side benefit of learning Vim, it's encouraged me to improve my touch typing because of the added benefit that you can type your Vim commands faster.
[0]: https://www.shortcutfoo.com/app/dojos/vim
[1]: https://vim-adventures.com/