I spent hours researching and tweaking my Garmin’s HRZ’s in my first year of running. It was the most important metric for me to follow and I think it helped me build a nice aerobic base.
As I’m only an amateur I won’t share anything specific but anecdotally, I found that once I dialed in where I “thought” (through many different self-test options I found online) my lactate threshold was and could start to identify that space between zones 3-4 I could then pull back and find my comfortable zone 2 space. After that I started manually adjusting the zones. I will say now I don’t use it as more than an occasional reference. I think a lot of folks (maybe?) migrate to using a combo of HRZ and RPE.
I’d say now I think I know what it feels like when I’m pushing past my lactate threshold and what comfortable and sustainable feels like and try to trust that.
Good luck in your running!!