Aerobic endurance vs aerobic power zone training

The heart rate zone approach is misguided and simplistic.

They aren't individualizing anything for you in any meaningful or enlightening way and they are also discouraging varied pace efforts where an athlete's HR would vary widely throughout. Moreover, elite athletes have a top gear that requires a race situation to manifest.

Your adaptations are primarily a function of duration and intensity, but for most runners returns diminish with too much of either.

Your goal is to run faster with less effort at any pace and to that end, 30' at a medium effort is often vastly superior training to 30' at very light effort.

True unless the goal is to recover from a hard workout

15-20M per week?

You're taking a very simple sport and making way more complicated than it is. Also, you need to run more.

You're a hobby jogger, judging by your name and the mention of Zone 1.
Throw the stupid watch away. FFS!
You will live just as long just walking. Fact.

One or two (or even 3) easy zones (below LT1)? That is a very good question, and it is not very well covered in science. Most science papers have only one easy zone and do not divide further. In the Norwegian training model (Ingebrigtsen, Blummenfelt and co) they do easy really easy, below 73% HRmax (60-72%HRmax).

If you are a little bit interested in zones , here is a video

LT1 is defined as Lactate threshold in this video.