I am not a royal watcher. (I have had to google a lot of the "other royals" in this this thread. But I know the "big things" that make the news.)
It sounds like Meghan was woefully unprepared for what royal life would be like. She kept blaming "them" for not supporting her, but it seemed like a lot of the blame should go to Harry. She had to Google the British National Anthem? Why didn't Harry teach it to her -- or at least give her a recording and let her know she needed to learn it? She was blindsided in the car on the way to meet the queen about the expectation to curtsy? Again, seems like Harry really dropped the ball, not "them." If Meghan thought she and Kate would be treated as "equals" then she was pretty naive (and again, Harry should have warned her because I don't think that's new. Did Sarah Ferguson ever have any good press? Again, not a royal-watcher, but I only remember the scandals, comments about her weight, etc.)
If she was in crisis and was denied mental health treatment, that's terrible. (And I can understand why someone in crisis, and in a newish situation, and in the middle of a big bureaucracy could have trouble advocating for herself. And I could totally see the powers that be saying "Do you really think it's THAT bad? The press will have a field day with this. Let's wait a while before we bring someone in from the outside. Maybe you'll feel better tomorrow.") But, again... it sounds like mental health is one of Harry's causes, and he's been through it before, and is willing to buck the system when necessary. Even if "they" wouldn't get her any help, why didn't he? I have to think that he also didn't think it was "that bad." (I'm not saying she's lying -- but it seems that Harry should have been her first line of defense/advocate -- and it didn't sound like he was.)
Regarding racism being the the reason that Archie wasn't (or won't be?) made a prince, I wish we knew more about that. It does seem like they threw that bomb out there without much context. If the royal protocol is that Harry's kids won't be princes/princesses till Charles ascends, and they're making the fact that he wasn't given the title at birth about racism, then shame on them. (And, again, I did not know the royal protocols before reading this thread, so I probably would have assumed that Harry's kids WOULD be princess/princesses... but even if Meghan didn't know the protocol, certainly Harry should have, and should have set the expectations.)
However, if they've already been told that Charles has no intention of making him a prince, and this was not mentioned till he was already conceived, then that certainly sounds "fishy." I have heard (even with my limited exposure) that Charles wanted to shrink the monarchy (although I had no idea how that would be accomplished.) However, if that meant excluding Harry's children, then that should have been discussed before Harry was expecting (or even engaged, really). Since it apparently wasn't, and it happens to affect the first non-completely-white members of the family, the optics are definitely not good regardless of the true reasons behind the decision. (I can understand how it would feel racist, even if this had been Charles's unspoken plan regardless of who Harry married.) At minimum it would seem smarter for Charles to name his current, living grandchildren as prince/princess per the tradition, then change the rules and make it clear that it applies to anyone going forward from that point.