How do you Balance Having a Life?

Like the title says. I have a 15 week old puppy and he's really good for the most part. We have in the last few weeks of having him overcome the worst parts of overstimulation, that made him a total menace to society. I know he's doing so well for his age, but I miss having a life too, to be honest.

We tried early to crate train him due to overstimulation, but quickly realised this wasn't Working out for either of us. He likes the freedom to roam and can settle alone, as long as he has something to chew on. However, the chew only lasts for like 15 minutes at Max. until he starts to howl, whine and bark. We've tried short intervals of 30 seconds with no reaction and he does just fine. He even does a few minutes-5 minutes just fine, but it's like he knows the difference between when I have to train it, and when he actually has to be alone.

Honestly, I need to be able to go grocery shopping for 30 minutes. I would like to take out the trash without worrying about him barking our apartment complex down and needing to ensure he's well prepared (peed, tired etc.) everytime I need go out with some trash. I would like to be able to see my friends again, go to a bar for a few hours, or something – at least at some point.

I know it takes time and I need to be patient, but oh my god I feel so isolated and all of a sudden the other issues of him wanting to greet everyone, locking his focus on them until they leave makes me so impatient at this point, because all I do is spent time with him and think about my next steps with him.

I see him worrying and wanting to settle for a nap on my lap to calm himself if I left him for too long, but good riddance, I need groceries man?! I don't know what to do at this point, I'm so afraid he'll get/has seperation anxiety, but I really don't know how to train it with him. He won't settle on his own, so it feels like the short intervals are in Vain (even though I know deep down they are not).

But like, in between walks, settling for naps, playing, chilling, eating, training etc. It seems so difficult to find several times a day where he's well fed and tired enough to train multiple short intervals of alone time..

So my question to you all is – How do you balance life and taking care of your pup, alongside training alone time and having a life that needs to go on beside him?