Not sure about the article in question but I would highly recommend ':help user-manual', it's actually mentioned at the end of vimtutor. It can be worked through chapter by chapter and covers all of Vim.
Ya that would be really helpful. I've picked up bits and pieces of vim over the years. Recently, I even installed vimium on Chrome and the vim extension for VS Code in an attempt to get better at it.
It has been quite effortless to delete or replace words or lines but every time I've tried getting more adventurous with it - say, surround every line of text with double quotes etc, I end up finding the commands unintuitive or hard to remember.
There's also an issue with my older muscle memory of `CMD+Z` which works on a different stack than `u` and `CTRL+R` and I end up messing up my code.