That sounds exactly like what one should do for, say, couch to 10k: build a solid base in "zone 2" (low aerobic), which also serves not just as a cardio foundation but also builds the body's ability to withstand effort and impact.
Then once the base is built, to make any progress one needs stronger, more focused stimulus, so you introduce interval training at high aerobic (tempo and threshold paces) as well as anaerobic (400-800 "very hard" sustained and all-out sprints) training, combined with a few zone 2 long runs.
And then the cycle repeats: you have to let the body recover so deload, then start a new cycle.
Nicklas Rossner has fantastic resources; there's a video there that explains how to find your current bottleneck: https://m.youtube.com/@NicklasRossnerPT
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.
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.