If they like coding and didn't want to prioritize career advancement I would tell them to put effort into finding the projects (or parts of projects) they find more interesting to code and make sure they get assigned that. My advice was always personalized. The thing is that for most early career engineers they are already coding enough (and it's not like the code is generally particularly interesting) so most of the time the advice is to do more docs since the lack of docs was hurting them for perf/grad but it varied from individual to individual