>>>Going to planets like Uranus, which has plentiful Helium-3 in its atmosphere, has one big problem: The 12-year round-trip time to bring it back<<
I thought Uranus produced Methane.
Uranus has high amounts of Helium-3. This article says that the Helium-3 high speed Helium-3 powered tankers could carry its cargo in 140 days round-trip. Each tanker would bring back a load of 614 tons using about 254 tons of fuel.
https://www.seeker.com/project-icarus-the-gas-mines-of-uranus-discovery-news-1765273832.html