How many times a day you try this?Not too often. I have been accused of having a different part of my anatomy in a different orifice.
You sound like bit of an expert on this.I've been tinkering with these LCD modules for about 20 years with at least four processor families and almost exclusively in assembly language.
Dealing with these LCDs is really very interesting. Like so many other things they are really quite straightforward once you understand them but they seem really complex when you don't. What makes them more challenging is that in some respects they require you to meticulously follow the data sheet and in other respects they are quite tolerant of deviations.
What really messes people up is that the various clones of the original Hitachi design seem to be tolerant of different deviations. So experimenter 'A' comes up with some not exactly correct code that works with his LCD and passes on this 'working' code. Experimenter 'B', with a different brand LCD, tries it and when it doesn't work for him he comes up with another version of not exactly correct code that works with his LCD and passes that code on....
Sticking to the original Hitachi recommendations is the best bet, but those recommendations are sometimes hard to decipher due to translation and/or editorial errors.