China has one big worry right next door.
Japan
and they have to keep two eyes on their back door - Russia and the Uighurs.
They have plenty of their own internal strife - which is the main thing that has always prevented them from extending beyond their own borders for millenia.
They have influenced through trade, threats, and diplomacy. But military expedition-wise they have very little history of success.
One of the biggest reasons for this is internally they have very little coherence - everyone is pretty much out for themselves or their group even when saying they are for the “emperor”, “party”, “kingdom”, or “nation”. Just have to read the histories.