Someone tell me this is just normal puppy exploration/behavior?

First time dog owner here.

Officially have had Frankie, our mini poodle for 3 weeks and he's now officially 13 weeks old! He's mostly potty trained with the occasional accident. Sleeps well in his crate 95% of the time. He's learning tricks. SUPER high energy and definitely doesn't have an off switch right now. Overall a pretty angelic puppy.

My question revolves around the fact that we have a lot of stairs in the house and his potty area for now before he can go on walks is on the roof so we have to take him up at least one flight of stairs, sometimes two. He was fine with us carrying him up until a few days ago and now not only squirms to get off but sometimes growls and barks. He's doing the same with his little carrier bag that I use to socialize him and take him on walks. He started actually barking today and biting the bag on our walk today for the first time. His biting just overall has gotten much much worse.

Is this just puppy behavior/finding his voice or aggression? Are we just in the trenches? Thank you!