I have a very unstable network connection -- what settings would best fit in Rocket League?
I don't think this can be mitigated by game settings. You may make a micro improvement by changing some of the performance impacting settings like shading or lighting, but in general I don't think it is possible to even slightly reduce the impact of dropping that many packets.
Even squishy suffers from this type of interruption at times, and he has been through every setting possible.