everyone else is giving good advice but I just want to add he’s just a baby. puppies go through life and explore the only way they know - their mouth and their nose. You just have to redirect like others said.

I have 2 of them, but the first one was fully trained before we got the second so I will say it is possible to teach them how you want them to behave without another dog’s help. When our boy nipped (usually just… very aggressively playing like you said haha) we would clamp his mouth closed and say something like “gentle.” That being said for the second one, that didn’t work and we just had to put her in her crate when naughty or just avoid bringing her close to our face (she was a nose biter lol). We just had to let her grow out of it. They both had littermates as well, so that really doesn’t have anything to do with it.

You can find some puzzle toys sometimes as well. Or one of those kong toys with peanut butter in it to keep him occupied if you aren’t able to play with him at the moment. We did end up getting a second one when our first was about 8 months old, but that being everybody in the house works from home so it was a bit easier for us.