Tommy, thanks for checking in. It’s not an 80/20 thing, but I can confidently say it is best-practice. Frequency is almost as important as volume for peak performance.
But, the best plan in the world is worthless if it does not meet your individual needs. Better to regularly train 4 days a week than 7 days a week most of the time.
You can modify any plan by merging the two shortest runs into the next two shortest runs, thus making your 7-day plan a 5-day plan (or a 6-day a 4-day). It’s not ideal, but it maintains the principle of volume and intensity balance for a small trade-off in frequency.
David