Anyone starting from the couch just needs to start. I started by just pursuing a goal of "run a mile without stopping", then 2, etc.

I've messed with zone 2 a bit and read a fair amount about it. If it gets you out there moving consistently: great. The best workout plan is the one you do. But otherwise I really think it's more of an optimization strategy for people who are trying to seriously increase their miles per week, and are pairing it with higher-intensity runs and/or weight training.

I was running 10km 3x per week for a few years. When I started swapping some of those runs for HIIT, performance on the remaining 10km runs very noticeably improved in addition to the cardio metrics.

To be clear, performance-maxxing was never the objective. I am in it for the health benefits and conditioning for grueling pursuits. Nonetheless, observable effects of different kinds of training on performance are still interesting to me and helps me optimize the time I spend on it.

There's a lot of noise and confusion about what exactly "zone 2" is and why. But definitely longer easier (you're not out of breath) runs build a foundation in more ways than just your cardiovascular system. It's those other components that take a longer time to build. The key is that you are not over-training (watch your sleep and joint pain as an indicator) and can recover and that you are progressively increasing your load by lessay ~10% distance a week. Easy system would be 2 shorter runs and one longer run a week.

There are plenty of online training program generators that are pretty good and will take you from zero to running 10k. I used an online program to run my first 10k somewhere circa 1990.

There a lot of more cutting edge science online (and I follow Nick as well) but if you're not a competitive athlete and are just trying to get in better shape then the answer is mostly just do it. Over some base of running you can throw in some interval training including HIIT.

Are you able to point out which video explains how to find your current bottleneck? I suspect its something I would find quite useful! Unfortunately most of the videos have quite "clickbaity" titles, which makes it hard to figure out what they are about.