Puppy struggling to settle when we are home

I have a 12 week old puppy who is great at settling when I leave the apartment and when it is bed time. However if I’m in the same room as his crate/ pen he really struggles to calm especially in the afternoons. He needs enforced nap times in his pen or he turns full shark but he just won’t sleep soundly unless no one is home. We give him enrichment, chews, short regular exercise, training and ignoring when in the pen. So exhausted with the overtired biting! Any thoughts welcome