Coming from someone who has been a tech, a position I got by purely sending out emails to PIs, before I start my PhD this fall, I was fortunate enough to land in a lab where I expressed my needs to become technically a lot better, while also working on mini projects which would be mine, every now and then. It was a large lab, and so there were lots of projects I could jump into, and I've been involved in three over the course of my time here.
So, while it is not research like a PostBac program, this position has honestly been the most helpful in making me a better baby scientist-in-training and for personal growth.