Hello,
If that may help, here is the part of my experience :
I had quite the same issue : I was wondering what is the good amount, because I was reading that we have so stimulate our puppy, but not too much because they quickly loose focus... So I started to check and an ideal schedule like "15 min physical, 15 min mental, potty, walk, nap, rinse, repeat"
with other information like "a walk should be 5 min per month of age", "training should be divided in session of 3 minutes max, 5-6 times a day"
And ended up with the worst experience I shared in the puppy blues topic, because it didn't match with what I read / saw / look on video
He ended being overstimulated because it was too much to tug and fetch for the time
I was afraid because one day he took a 4 hours nap, while I heard a session should be "1 hour awake, 2 hours nap"
I've made the vet laugh when asking him about that being more anxious than ever... his answer : "there could be a million causes : he's too hot to play, he has a growth pikes, teething pikes... if he plays with you while awake, still eats, bites you, he's good..."
I even asked here just to have Adrienne reply "it's a baby, just let him sleep" :) :)
The real thing is that any pup is different, will evolve differently, and once I accepted that, and learned to read the signs on my pup, everything went better
He has a 2 hour session following by 3-4 hour nap in the morning
In the afternoon, he just wanders around sleepy because it's starting to get a bit hot... I try to catch few minutes here and there to make some basics
starting 5pm, he begins his day, and this time it's a 2 hour awake session, with a 1h 1,5h nap during which we take dinner, and then last session before bedtime
I'm not sure it's a recommanded, or convential schedule, but it appears to work for us and Loki. I feel less anxious, and time we spend together are really more quality time, instead of just trying to do "what is needed, and what should be done". We just enjoy together
About training and consistency, Adrienne has so much quality content I'm not even sure another source is needed
One thing though : nobody in mainstream article tells you how much it is long, and how much patience you need, and how much to repeat, rinse, repeat...
They all try to sell the "quick magic method that works so fast"
Personal case : we trained "leave it" so much, again and again at home, and he still took everything he wants during walks... but still, we continued, again, and again, and again... and one day during a walk we said "leave it" on pile of horse poop (high value to him), he looked at us, cross over without touching... my gf and I looked at each other, I thought we were gonna cry in joy !
It's become easier as you understand that it really takes time... It's not us owners that doing badly (given we make the effort to make it right), it's just long and it's normal
Training definitely does not give short term satisfaction. Don't get me wrong, a good session is always nice to have, but the biggest reward comes after time and dedication, when he managed to do something you struggled on, and though was so hard
So I'm pretty sure that with the caring you show (just being here on this forum is almost some kind of proof of willingness to do good), he will end up really well behaved