I'd argue that once you have a very well defined requirement doc that mostly kicks humans out of the picture, as well as a patient boss who doesn't want anything ASAP or "Tomorrow morning first thing", engineering is not that hard, and is almost...enjoyment.

Based on the communication fix, they also didn't have a simulator, or tests, or complete source code, on a custom instruction set that wasn't well documented, so they had to reverse engineer how it worked. https://www.youtube.com/watch?v=YcUycQoz0zg&t=2366s

That was ballsy! But, sadly, it was a temporary hack. Both Voyager have degrading, unfixable thrusters. The rubber diaphragms in the hydrazine fuel tanks are degrading, shedding silicon dioxide (i.e. sand) microparticles into the thruster fuel. These particles are gradually clogging the thruster nozzles and reducing their thrust. Eventually, thrust will decline to the point that they could fire the thrusters all day long and still not impart enough momentum to point the probes at Earth. Once that happens, we'll lose contact with the probes.

They'd switched away from the primary thrusters in 2004 due to this degradation. Now the backups are so degraded that the primary thrusters are better again in comparison.

Thruster clogging will kill Voyagers in about five years if nothing else gets them first. The least degraded thrusters nozzles are down to 2% of their diameter --- 0.035mm of free-flow area remaining.

The Voyagers will probably celebrate their 50th anniversary, but not much beyond that. :-(

Kind of ignominious to be done in not by the inexorable decline of radioactivity but by an everyday materials science error of the sort we make on earth all the time. In the 1970s, we knew how to make hydrazine-compatible rubber. We just didn't use it for the Voyagers.