So, if I'm having a problem w/ dockerd (via docker pull), how likely is it that switching from mobyd to containerd (using nerdctl) would fix my problems?

It's hard to say if switching to containerd will help without understanding what's causing performance issues for you. Has this been like this for you? Or is this something you started experiencing lately?

Just tried containerd. It didn't change things significantly. It's been a problem for a long time and only to gcr.io