Have there been reports that Meghan is upset about the work that's expected of her? That seems to be the part of her position that she enjoys the most, she started doing engagements with Harry very soon after their engagement, she was doing engagements without Harry almost immediately after their wedding, and she played at least some role in the Hubb Community Kitchen cookbook and Smart Works capsule collection projects. Plus she always seemed very enthusiastic and engaged during their tours, which involved a lot of 'go to this place and look very excited about this small organization's achievements' type work. If anything, I've read complaints that Meghan was perceived as being too enthusiastic (read, American) about taking on work.
Harry and Meghan's complaints about their roles seem to be pretty directly tied to media coverage. That they think that the coverage of Meghan (and Harry by association) has been offsides and that, because of the existing arrangements between the press and the Royal Family, they aren't able to respond to the coverage in the way that they'd like to. Harry also seems to be very angry (through comments from 'sources close to...') that his family hasn't been more receptive, privately or publicly, to his complaints.
Also, I don't think that it's necessarily a positive thing that an institution that is supposed to serve as the ultimate representative of the Commonwealth has been so inhospitable to newcomers who don't fall in line with the way that things have always been done. A lot of negative press that the Royal Family has received in recently years (Diana and Charles' divorce, Diana's death, the racism gaffes, the Epstein debacle) seems to result from their lack of understanding of how their actions appear to "ordinary" people. I think that they would benefit quite a bit from having more "commoners" on staff and in the family that they actually listen to.