Maybe Elon Musk could launch a couple of his Starlink satellites into deep space and reduce that latency.
That or apply xkcd #303: https://xkcd.com/303.
That or apply xkcd #303: https://xkcd.com/303.
Also throughput could be increased by changing or updating the modulation and coding schemes. AFAIK Pioneer and Voyger probes were still using PSK and FSK.
In the former case, a relay could help quite significantly.
In the latter case, it would just add even more delay.
Deep space RTT is unavoidable.
More hops = more latency. The fastest way is a straight line between origin and destination.
Sorry to say, this limit applies to Elon Musk and his satellites as well.