I noticed in the tags of a reblog you mentioned "there is no such thing as a feminist retelling." Could you say more on that? I'm relatively new to Arthuriana and have heard that term used to refer to Mists of Avalon - which has put it in the queue behind my current reading, frankly. I'm curious if it's a failure of language or something else.
Feminism is the belief in gender equality and a movement with a goal toward women's rights. In my opinion, a piece of fictional media cannot be feminist in and of itself; it's not alive and cannot act on its own. Media can communicate feminist ideals, it can be a tool of a feminist to illustrate her advocacy for women through storytelling, but I think over time people have come to mistake media consumption for activism and labeling books (or any other media or merchandise) feminist only exacerbates that issue. So long as reading a feminist fairytale is considered feminist action, the movement grinds to a halt and ends at consumerism. The term has now become a marketing label used by fiction authors/publishers to make money. We've been sold the false idea that reading "feminist" fantasy is akin to aiding the political movement. It isn't.
I also believe that people should be striving to write feminist works automatically. One can write a story which upholds the author's feminist theory without a woman at the forefront, even. If there are plentiful women with narrative impact and importance and the subtext humanizes and respects them, even if they live in a patriarchal society and the pov character is not a woman, that can still be a story which aligns with feminist values. For example, I just read The Story of Silence by Alex Myers, in which the point of view characters are an unnamed bard (a cis perisex man), Cador (Earl of Cornwall, another cis perisex man) and his child Silence (born female but raised male and identifies as such for most of the book) and Myers went out of his way to respectfully depict women that the original Medieval poem demonized. I would consider this to be feminist-aligned, particularly bc the story itself ruminates on gender inequality! Nowadays, especially since Marion Zimmer Bradley's The Mists of Avalon, marketing teams simply label any Arthurian retellings starring a woman "feminist" when half the time they're still misogynistic (or racist, or transphobic, which is incongruous with intersectional feminism and voids any supposedly feminist intentions)!
And on that note... I encourage you to research Marion Zimmer Bradley's history before you decide whether or not you want to read her work. Zimmer Bradley was lauded as revolutionary in the Arthurian genre and a feminist in her time, but since her passing, her daughter, Moira Greyland, has written her own book, The Last Closet of Avalon, which details her life long sexual abuse at the hands of both her mother, Marion Zimmer Bradley, and father, convicted pedophile Walter Breen. Hindsight is 20/20, and looking back at The Mists of Avalon, there are undoubtedly some disturbing aspects which hint at the warped mindset held by and acted upon by Zimmer Bradley and led to the violence against her children.
For me personally, I don't feel comfortable recommending the book (or 2001 TV show), even for the morbidly curious, now knowing that it transcribes the abuse suffered by Moira Greyland and her siblings. It feels exploitative and voyeuristic. The irony that the works of Zimmer Bradley are called "feminist" and still referenced as such to this day, without any caveats, is nothing short of horrific.