Mmm

It could be prequel. This could be what they meant by them still having Wenwu in the MCU's future without taking away from the impact of his death

Is it about Wenwu or Xialing?

Because:

1. Wenwu is one of the best Phase 4 villains so that would be good; plus it could show what he did in the past that led to the Iron Gang killing Ying-Li.

2. Xialing’s story will clearly continue. The post credit scene confirmed it. Whether her intentions are good or evil is yet to be revealed so that would be pretty cool

I thought a Wenwu show might be between Lis death and Shang-Chi's present, but one from before might work too (and is kind of supported by Fala Chen saying she would be in future things)

A Xialing show makes sense, but I honestly don't know how relevant it would ultimately be. After the Agatha show thingie, I think Marvel is milking too much from the spin-offs.

Spin-offs were kinda the point of Disney+ shows thing anyway, like WandaVision, The Falcon and the Winter Soldier, Hawkeye, etc. Like yeah there are introducing more characters but Disney+ was ultimately to tell more stories that doesn't really fit the continuity of movies. Also, from what I see it's kinda the period of various producers pitching show ideas, like Monica one and this. There are probably much more shows but who knows how many of them will get greenlit.

Well, at least most of the shows we got make sense. A spin-off of Wanda and Vision, Falcon and the Winter Soldier and Hawkeye are spin-offs that were craved by Marvel fans for a while now, given the characters have been in the MCU for years. A spin-off of Agatha and Monica and Xialing feels way too soon. I just don't see an imediate motivation to do it, in my opinion. I feel more interested, in contrast, with brand new characters that come along, like Ms.Marvel, Moonknight and She-Hulk, whose introduction is meant to be a first on their own show.

Yeah and that's why we are getting these ones sooner, Again, most of these new shows are at pitching stage, and some might not even become a thing.

It does bring up the question why those pitchings are being publicly revealed. Or is it just rumor or leak?

I wrote "rumor" for a reason there. Yeah, Monica and Ten Rings are rumors, while Agatha's one was from the Variety's insiders. Marvel didn't make a statement about any of those yet.