I think, and of course none of us really knows, but I think Diana was in love with Charles when they married. I don’t think she was in love with the prestige or wealth because she already came from a prestigious and wealthy family. I think that Charles was not in love with Diana, but I do think he cared for her, he has admitted she was extremely pretty, so we can presume that he found her very attractive. The problem seemed to be that they had little in common except the lifestyle, and even though Diana was used to wealth and prestige, she none the less found the royal family stuffy.
To be honest, they probably were.
The people loved Diana precisely because she wasn’t stuffy. She was able to relate to the people she met, and she showed her love for her children openly, and the love she gave her children helped them to grow up to be much less stuffy. (I think Charles loved his sons too, and he still does.)
Going back to the Meghan and Harry scenario, it would appear that Meghan thinks she can be Diana’s successor. She can’t, she’s far too me, me, me!