That stage is so fun but so scary! My best recommendation would be to avoid letting them learn bad behaviours. Always have a lead on so they can’t run away, make a big deal of it when your pup comes to you even if they weren’t called, you can easily add a Que to it by saying ‘good come’ dogs learn super fast with repetition.
The chewing sounds a bit like boredom or nerves because you aren’t there. You could rotate the toys you leave out, leave some calm music playing, try leaving some enrichment toys, ie peanut butter spread in a tube or treats rolled up in a blanket. You could also purchase a camera to check in occasionally and be able to speak to your pup.
Enjoy the puppy love

they definitely go through a curious phase and want to run towards anything and everything, especially out in public! definitely keep him on leash until he can be trusted to avoid any potential harm or accidents. i would definitely look at some puppy school or training to help you, there are also fantastic resources online on youtube etc these days that can get you started.

Is he about 4/5 months old? What is this toddler stage they go through?!?! It is like they lose all intuition of social cues and go into hulk mode on anything that the sun hits slightly differently. In terms of reprimand so far the only thing that has worked for us is a spray bottle. It seems to snap him out of hulk mode. Keen to see what other people suggest.