Oh OP I am so so sorry you're going through this.
I had a very similar situation, on maternity leave with new baby, just bought our house and next door were absolutely horrid. Very similar to you, drug dealing, riding around on dirt bikes, they even kept riding them up and down our driveway and telling me to fuck off whenever I told them to get off. Like you it would wake my baby up.
They were very obviously stealing bikes and cars too. They had a toddler, no idea how he'd not been removed from them tbh poor lad.
I like you was too scared to leave my house, they'd all congregate outside revving engines, smoking weed, shouting etc...
Weirdly they seemed terrified of my husband who'd had words with them before and would stop if he was in, the minute he went to work though and they knew it was just me they'd start again.
Even down to the dog which they'd leave locked in a bedroom upstairs howling all day and night.
I too was scared to report in case they knew it was me. Every single person on the street despised them.
I'm sorry I don't have the answers, we were very fortunate in that they suddenly got kicked out (they were renting). All their stuff was on the front garden one day (it rained as well which just felt like the best karma lol) and they were gone. We now have a lovely couple with two young kids next door who I get on really well with the mum.
I was ready to move and absolutely would have by now I'd they'd not left.