To my knowledge Princess Anne, Prince Edward and Prince Andrew (when he was in the fold and worked for the Queen) now only get protection when they are working. Their personal protection was taken away in a cost cutting exercise I believe.
So even if Archie was given a Prince title, he still may only have protection paid for when he works on Royal Family duties.
The issue for Meghan and Harry is that they believe Archie and his soon to be sister will probably have more potential threats than others because of their mixed race. And the royal family haven't really addressed that concern. Possibly because they haven't even thought of it as a bigger problem than Zara Tindell getting kidnapped by terrorists or Princess Eugenie being attacked. From the royal's point of view Anne Lawrence is OK to run her farm without protection, whereas she'll get it when she's Princess Anne opening a factory so what's the problem? They've not thought of the added race issue (or have chosen not to because it opens up discussions about Eugenie, Zara, Peter et al)
But, going to Oprah and making out that the Prince title was dismissed because of his colour based on a conversation that Harry reported back to Meghan shows how little Meghan did in the way of research. Surely Harry should have explained the succession to her? Stopped her making a fool of herself with that comment? But then this is a man who apparently heard a conversation about his future child's colour, didn't call the person out and went straight off to tittle tattle to his mental fragile wife. But, apparently that's OK in Meghan's eyes - it's the fault of the person who said it (definitely agree) and not of the man she married who wants to share every conversation with her (not what a normal person does).
Harry is also the man who didn't call up friends to sit with Meghan on that gala night when Meghan had told him she felt suicidal. If my DH had had to work (i.e. attend the gala) I'd have expected him to come up with an excuse about why I couldn't be there and ask a friend to sit with me on the pretext that I wasn't feeling well (being pregnant) - not expect me to get dressed up and attend. To then bleat that she had to go and not have a word of admonishment for the lack of support from her husband in the first place is astonishing. But that wouldn't meet her and Harry's agenda of the two of them against the world - poor souls.
And the issue with the national anthem and the 'institution' not allowing for Meghan struggling with it being from a different country? Again Harry didn't seem to help her with that. It's not hard. Neither is learning these 30 hymns she mentioned as part of that 'nobody helped me' scene she played out. She's an actress used to learning lines with very short notice. If Harry had briefed her it wouldn't take her long to get 30 hymns under her belt. But it seems he didn't take her to one side, sit her down and go through these things with her.
Also Meghan mentions that Harry asked her if she knew how to curtsey when she first met the Queen. She knew she'd have to do so in public but didn't realise it was done in private. Despite me knowing that from Hello interviews done with Kate and documentaries showing Princess Anne doing exactly that. But there you go. Maybe she expected a few folders and videos to be given to her as an engagement present. But Harry is supposed to be her loving husband. He shouldn't have just thrown that comment into the mix minutes before Meghan was due to meet grannie. Again, Meghan has forgiven him and turned the blame on 'the institution' rather than where it belongs. With the lump sitting to her right in the interview. What sort of man does that? If he can't think of Meghan's needs then why would an extended family? I don't expect my uncle to brief my husband about what to say to whom at a family party. I do it. He's lived with this parade all his life but can't think his way around what his wife would need to know to settle in quickly? Seriously?
Personally I think Meghan needed to look very closely at the 'man' with her in that interview. He may have been able to brief a battalion of men in battle but he's got precious little idea about helping his wife and guiding her other than to run away.
All they've managed to do, I think, is give the signal that the gloves are off. The Queen etc may be constrained in what they can say but friends, Meghan's family et al aren't. Thomas Markle is already starting the rounds and Meghan can't complain when more stuff comes their way. She and Harry have shown that the way to get your point across is to speak to the media.
Could be a case of be careful what's contained in the can of worms you've just opened.