Hiya!
I'm new here too with my 17 week old wcs puppy Oscar. We've had a baptism of fire too!!!
a lot like you... toileting and sleep at night is going well, mouthing everything is a challenge!
We have a crate in the kitchen and a pen in the living room. He tends to be with us and we give lots of attention in the pen... but the crate is for sleeping and we try to use it when (or ideally just before!) He gets overtired and a bit wild!! We have kids in the house so I worry about him eating a piece of lego... or anything else that has been dropped so we can't give him as much freedom in the house as he would like. He gets walks and outdoor play too so I try not to overthink the pen thing... it's not forever and better than a vet visit! We train good behaviour in the house, out of the pen but on a long lead. This is when I've done a final sweep for lego, pens, homework sheets etc.
The garden however, we do let him have free run of. He mouths stones, he picks up snails, he has picked up (but not eaten) a slug. He has also popped three footballs which had to sneak into the bin
I swap the stones for a piece if ice sometimes, he still gets that hard bite but without me panicking - I try to otherwise ignore the stones and after watching him carefully he usually drops them after exploring them for a short time. I keep a garden trowel close by at night and do slug patrol whilst he has a wee
and chuck the slugs over the fence. I also cut back the big plants so I can see the base of them and raked out all the old leaves etc where snails could be hiding... he likes those too!!! And the kids footballs are away for now!!! Basically, I've puppy-proofed as much as I can so that he can enjoy it.
Someone here suggested not running after him if he has contraband (it might well have been cazza!) so I ignore him or if I really need the thing because it is dangerous... I pretend I'm making his tea. That gets his attention and he comes running.
I dont know if that helps. But you're not alone!!! And if we ever manage to move beyond the pen... I'll let you know