Yeah, I guess isn't not really about simple vs. complex for me, I don't mind having to research, break down, or even delegate; but I want to clear goal. "Improve the login flow" is a task I hate, and probably won't do well or fast. "Allow Yubikey as an alternative to Google Authenticator for our 2FA" is something I can knock out, even if I'm totally new to the code base (and I've not yet ever used the Google Authenticator API or a Yubikey).
I know metrics make for poor goals (Goodhart's Law) but I like a task that is metric-driven. I do tend to be careful to not be overly fixated on the metric and rather the improvement it's meant to reflect.