Puppy is a demon - is this normal?

We have a cockapoo male who is just over 4 months old. To begin with he was an angel and the only issue we had to worry about was house training, which he struggled to get but seems to be slowly getting the hang of. However, in the last 2 weeks or so he’s turned into a completely different dog. I’ve listed his most concerning and most frequent behaviours below:

• He is constantly biting us, and often lunges towards our faces (he’s teething and has lost a couple of teeth so expect some of this to an extent but he’s incessant with it and doesn’t stop no matter how much redirecting or trading for higher value items we do)
• When he’s not biting, he’s constantly searching for something to steal. It doesn’t matter what it is, if it’s not completely out of reach or nailed down, he will take it. Examples have included cushions, shoes, clothes of any size, phones, tv remotes, cutlery, papers of any kind, bags. The list could go on. He refused to give it up, again no matter how much redirecting or trading we try and do, so the only way we’re able to get anything off him is by forcing it out of his mouth. And even then he tries to snatch it back the second he loosens his grip. We’ve been teaching him to “give” with toys but this command has in no way translated to other items.
• He is way too rough with other dogs. He will try to play fight every couple of minutes and he completely ignores the cues from the other dog that they’ve had enough or he’s doing too much. He also ignores any interception from us or anyone else and will just keep trying to get to them by whatever means necessary.
• He seems to completely ignore any kind of command, even though we’ve dedicated time to teaching them and know he gets it when in training mode, and we’ve even tried introducing forceful/stern voices to try and make him understand when he’s doing something he shouldn’t, but whenever we try and tell him off in this manner it has the complete opposite effect and he starts to misbehave even more.
• I know many of you will question how much enrichment and exercise he’s getting, and we’re doing absolutely everything we can think of to keep him entertained and stimulated. He has kongs and snuffle mats regularly, he has lick mats and chew toys, he has a flirt wand we use regularly, and we’re always trying to get on the floor and play with him. We have training sessions and we run around in the garden with him multiple times a day. He has a long walk for his age every day (up to an hour but never less than 30 minutes) in large green spaces where we try and do off lead work with him. If there’s more enrichment we should be doing, I don’t know how it would be humanly possible.
• He’s not crate or pen trained because we chose not to - I realise that this may be our only option left but I would like to avoid it if at all possible.
  

I’m making this post to try and get some advice or assurance. I expected a level of poor behaviour in these early weeks because he is a baby and he needs time to learn, but this feels absolutely excessive and he feels completely out of control. I know he’s not doing any of this on purpose but I’ve had puppies in the past and none have ever been this persistently poorly behaved. Is this just par for the course of most puppies? Are we doing something obviously wrong? Do we just need to give it some more time?

Please help this exhausted and exasperated new puppy parent!