It's tough leaving them, I know exactly what you mean! I'm working 3 days a week right now. This is what we do (we have 3 kiddos). Our master bedroom is open to our master bathroom - so during the day, they stay in the master bathroom (fenced off) which is very open, has a big window, 3 dog beds + pillow
, pee pad, toys, water, running space. I would never want them wandering the house bc it just wouldn't be safe.
I think it sounds like you have good options either way. What if you did both? A couple/few days a week do one option, then the other days - do the other? That way, he'll be used to both too, and it's good for puppies to learn flexibility. And also, my dogs sleep soooo much during the day (as in, when I'm home with them) - so keep that in mind too; your baby will spend a lot of time dreaming
.