I live in Japna and have a high-intermediate level of Japanese. I wish I had been able to read and think about these well-expressed observations when I was just starting out as it would have saved me from having to intuit things over time.
Like Cure Dolly writes, no one tells you what you really need to know when you're learning Japanese (all languages?)
I found Cure Dolly's guide very helpful as a launching point for Japanese. Just don't take her "all you need" marketing too seriously, it is more an introductory level than a complete guide.
I'm so glad someone is taking these forward. Her videos were a god send when I started out learning this language. Besides the sometimes strange rants about text-books, her videos are top notch.
This looks like it took a lot of effort to transcribe with all her helpful graphics too.
Thank you for doing this!
R.I.P Cure Dolly
Another great source is https://imabi.org/
I did some digging into the identity behind the Cure Dolly character after finding the videos quite helpful. There is what I recall being a fairly credible trail of evidence that the proprietor is formerly associated with the Silver Sisterhood, AKA the "Lesbian Spanking Cult", which has popped up on HN a number of times due to their involvement in the early text adventure video game industry.
For people not in the loop, Cure Dolly was a youtuber who taught basic Japanese grammar lessons using a digital avatar. She had (and continues to have) a cult-like following (in a good way) among a section of the online Japanese learning community. She was also ill at the time and eventually passed away.