That’s an escalator that China can’t afford to ride.
The US would deorbit everything China ever put into space if they started shooting at satellites. Those satellites are part of the strategic triad and would be a direct threat to the US nuclear umbrella. The AEGIS systems off the Chinese coast would take care of any attempts to add satellites back into space.
Low-Earth orbit satellites are not currently part of triad (but may be part of a future nuclear defense shield / interceptor system). They are also much easier to shoot down.
If China didn't care about international law it would've said it sent the balloon on purpose. Instead it found a cover story of some civilian balloon gone awry. They cared enough about international law to lie.
International law’s got nothing to do with it.
Basically Every spacefaring has made it their policy that an attack on one of their satellites would be treated as an act of war and everything would be on the table in terms of retaliation
I wouldn’t put it past the Chinese to deploy islands of atmosphere and release air in low earth orbit, and then declare that it is now part of the Chinese atmosphere before they start shooting down satellites.