Won't ion engines power by something like Kilopower reactor let us do better?

Bunch of napkin math: you'd need something like 10 kilowatts and 140 km/s detla-v to catch up to Voyager in a decade, assuming a New Horizons equivalent Earth escape velocity. The amount of xenon is technically possible, however even assuming impressive 8000 Isp thrusters, your fuel mass fraction ends up being 90+% fuel which doesn't leave a lot of mass for that reactor and radiators.

A 20 year intercept would be pretty reasonable though. It needs about 15 km/s delta v after that NH style escape, about a kilowatt of power, and maybe a 25% fuel mass fraction at 6000 Isp. That's all very reasonable by current standards.