It doesn't affect the stealth that badly. It doesn't help, but it doesn't really hurt it. It's not a true VLO platform, but a LO platform. It's
basically designed to get into range of our high value assets, and be the sensor portion of the sensor/shooter and allow other assets to use very long
range missiles to target them.
Janes as stated there are at least 132 J-20s in military service. The scuttlebutt from the sinophonic internet is its really about twice that. Folks
have been counting birds coming out of the factory and the tagging tail numbers once they are painted.
TBH, I think they're probably right. More combat ready J-20s than F-22s...and China only needs to worry about its borders.