In the event that exercise becomes a persistent habit, what is optimal changes a lot over time as you age and as you improve.

Speaking from the perspective of having exercised 5-7 days a week for over 20 years now, doing both strength and endurance work, I can say that my interests, capabilities, and my response to exercise has changed in fascinating ways over that time. Most people don't stick with an exercise program long enough to even really understand it, let alone wear it out, but if you do, what you do will probably change a lot.

I realize that's a pretty vague statement, but while I think your advice is pretty good overall, the idea of optimal is not something that stays fixed over long periods of time.