He sounds to be having a lovely life. Firstly puppies need a lot of sleep. My lab is 2 and spaniel 5. After their morning walk and breakfast, they sleep. They sleep happily lots of the time. Dogs need to settle. I worry about Facebook groups obsessed with ‘enrichment’, rather than good routines, and balance between exercise appropriate to their age and breed needs.
Have you had him weighed at your vet or are you noticing him looking thinner? Our vet is happy for us to pop in any time to weigh our dogs. They update the records every time I call with one of mine. My spaniel gained weight and became lethargic, sleeping too much. It was thyroid problems so soon sorted with meds.
I know vets are expensive but if you’re worried a health check and suggestions about feeding may help. I pay monthly it covers two six monthly health checks as well as immunisations, flea/worm etc.
Schnauzers are very cute x