How stealthy is stealthy? From what angle?
RCS is different by aspect/band and nothing can be all aspect, full spectrum stealthy by shaping alone. If it isn't stealthy from the bottom or top aspect - as almost nothing is due to the need for control surfaces and fuselage - then it can be shot down from above by CAP and or shot down when it overflies an unexpected SAM or AA gun site.
Nothing prevents a hypersonic missile (especially an unpowered glider stage since it doesn't need wings or an engine) from also having a small RCS, with the difference that even when detected there might be nothing that you can do about it since it is flying too high for guns, too fast for standard SAMs, too fast to move the target away if possible at all, and you can only rely on 1v1 terminal phase interception with the most expensive specialied SAM munitions.
Imho the most interesting development is the CJ-100 missiles, which seem to have managed to boost up a stealthy cruise missile to 4-5 mach. It's likely highly expensive and there isn't much of the CJ-100 deployed. However, if it works as advertised, it would be one of the key weapons in any Taiwan defense scenario.
The DF-17 and DF-21/26 are chaff weapons, the former is produced at same cost as Tomahawk. Likewise, the CJ-10 missiles are even cheaper. Technically the DF-17 might work similar to the Avangard, but unlike the Avangard, it is not an one of a kind weapon, it's cost allows for mass use.
In order for a successful US invasion, multiple aircraft carrier groups need to be able to enter the vicinity of Taiwan and then operate there until enough troops have been deposited to launch further offensives. If only 1 or 2 US CV or large amounts of escort ships are sunk early on, there won't be a way to supply the American forces.
In this environment, China will launch all the older type kinzhal equivalents along with newer HGVs at the invasion fleet. We do not know if the latest SM can shoot down HGVs, but even if it could, it the midst of this battle, there would also be sea skimmers coming in at hypersonic speeds.
If just a few missiles get through to the US carriers, the whole attack might as well be scuttled in terms of its momentum. Especially after seeing latest block Patriot failing to take on air breathing ALBMs over Kiev, China would have greater confidence that it's missiles can scuttle an American force before US even manages to attack in earnest.