Mitigation might have to involve some sacrifices. I don't see how policy is going to be able to mitigate much here. And of course the Chinese are under no obligation to listen to US policy makers. They might have their own debates domestically around this topic and they might be reasonable about the topic internationally even. But building international consensus; or even enforcing what little there is on that front could be challenging.
A more practical approach might be accepting that earth based observations are inevitably going to suffer a bit as the number of satellites grows from thousands to tens of thousands and eventually well beyond that. Luckily we now are able to launch stuff into orbit a lot cheaper. Including astronomy related hardware. That's already happening of course. And otherwise, astronomy is very interesting and cool but mostly it concerns observations about things that are really really far away and not directly relevant to a lot of things on earth. Unless of course the thing under observation is on a collision course with us.