That's simply untrue. The Sukhoi SJ100 is a different type of plane (<100 passenger capacity), comparable to an Embraer E190. Neither it nor the Comac C919 are "widebodies".

The C919 is a decent plane, but by most accounts a decade behind in tech and efficiency. And for short-haul operations, efficiency is the most important thing.

The only real competitor to Boeing today is Airbus. Comac can be one 10-20 years down the line.