Yep having the hardware is only the first step. Using it right is a different matter and it doesn't have to just do with training hours but careful and creative mission planning.Adding on to explanations by @Totoro and @Wrought:
Stealthy ≠ Invisible to the enemy
Stealthy = Less likely/more difficult to be detected when at shorter distances to the enemy
Being stealthy can indeed do wonders when everyone else has literally zero means of detecting you (that's basically how Saddam's various command centers in Baghdad gone up in smoke in the opening hours of the Desert Storm) - But that simply isn't the case anymore today.
Having the capability to (at least sometimes) reliably detect and track (V)LO targets is certainly a matter of fact for China today. Hence, it should be assumed that the opposing side (namely the US&LC) will also be equipped with similar, if not equivalent capabilities, if not already done so.
Therefore, instead of having H-20s going headlong through the networks of radar and sensor platforms that are lining the 1IC alone, it will have to be done with a throughout combination of efforts across a multitude of dimensions and spectrums through effective integration across various branches of the PLA.
Also assuming strong opponents will lead to vastly different mission requirements and solutions than assuming weak opponents.