Separation Anxiety & Leaving the House

Hi everyone! I have an almost 5 month old Labrador that I rescued at 15 weeks who is amazing in a lot of ways. He is great on a leash, listen really well for a puppy, doesn’t bite much, etc. Overall he’s a total sweetheart and going to be a great dog.

However, he has horrible separation anxiety when I leave the house (he is crated when I leave). In terms of his crate, he seems to be indifferent to it. He willingly goes in there to sleep at night, will eat his meals there, and will go if I tell him to for a nap (with minimal whining these days if he is really tired). The crate is currently in my bedroom because if he can’t see me he won’t be able to fall asleep. I have tried covering the crate when I leave and he doesn’t seem to love that either.

Anyway, the biggest issue is that when I crate him and he hears me leave the house, he lasts about 10 seconds before barking and whining. I have been “leaving” 3-5 times a day for a strict 60 seconds for the last 2 weeks and it hasn’t gotten any better. I was planning to keep doing the 60 seconds until he got better then move to 90, 120, etc., but he doesn’t seem to be making much progress. Does anyone have any advice on what to do here? I want to be able to leave the house for an hour or two and not worry about my neighbors hating me or traumatizing my pup!

Some things to note: – I live in an apartment and received a noise complaint when I left him for an hour (I didn’t know he was barking and whining) so I want to be careful around his noises but also need my life back and want to be able to leave my home! – I live alone but my boyfriend has been here a ton so that he is never alone – He doesn’t fairly well when I go to shower, use the bathroom, etc. but he just always wants to be around me (I can hear him walking up to the doors when I’m in another room). He will also go hang in another room without me sometimes, which I feel like is good? – He had a foster before me who kept him in his crate in the dark in a laundry room when they would leave and at night, so I wonder if he has some trauma from that? – I have seen some improvement with him being alone in another room, in his crate alone, etc.