I've enjoyed Shang-Chi stories, but how many people, even comics fans, know who he is? Can't be much demand there.
Black Widow should work out for them. People are invested there. Dr.Strange probably does well and watches well.
I don't understand how they think Eternals is an appealing option. Those guys can't even make it as D-listers.
They might discover the line between genius or hubris, or they might pull it off again, but ugh.
Shang-Chi is the least known project, but China is the second largest box office behind the US. The casting of Tony Leung as The Mandarin is a big deal: a US-based comparison would be when Robert Downey Jr first landed the role of Tony Stark/Iron Man. That movie could not eclipse $200 million domestically, but could still gross over $1 billion. Marvel films that play towards an international audience have done well:
Iron Man 3 made over $800 million internationally. That version of the film had 4 minutes of extra content that was only shown in China.
Age of Ultron also made $940 million overseas and part of that was due to filming in South Korea and casting South Korean model & actress Claudia Kim as Helen Cho.
The best comparison may be Days of Future Past which cast Chinese actress Fan Bingbing as Blink. That movie made $230 domestically, but over $500 million internationally thanks to that casting.