One thing that the MCU hasn't been spectacular at is branching out into other genres. Most have been scifi/fantasy fare. An attempt at horror with "Doctor Strange in the Multiverse of Madness." Some more comedic entries like "Thor: Ragnarok." "Shang Chi" is their attempt to bring the classic Kung Fu fantasy genre into the fold. And it sort of works. It's not wholly original in the idea, but can be taken more as a tribute to the Kung Fu fantasies of old. There are some changes made to established Marvel lore, but nothing that couldn't be lived with and accepted and really are necessary for the story. The story is good, not great, the performances are mostly good. The effects...are mostly decent, but there are some issues. The constructed sets are good, but the green screens are obviously green screens.
The main problem this movie has is that it shines a spotlight on a problem the MCU as whole is developing, which happens in the comics and any long running shared universe: It's getting really bogged down by its lore and interconnectedness. It not good for newcomers to the MCU and will likely only appeal to fans of both classic Kung Fu films and the MCU films.
It's good. It's entertaining. It provides some new stuff for the MCU, but it falls short of actually being a great film.