My sympathies. I read your post and quickly ran outside into the rain to cover up my veggies with an old cold frame. Had put them into soil just hours ago but forgot the cover. So for what it's worth, you may have saved 20ish little cabbages, carrots and beets today :)
They do help break things down, but unlike most helpful bugs they prefer the produce. I have just never seen them like this. We usually have to take countermeasures against them every year, but this year is we're just swamped.
I'm gonna do some work out there this weekend. Think I'm gonna get aggressive with the DE because I think I'm also having some trouble with woodlice. Do some tactical earth salting around the beds
I'm trying used coffee grounds and some other stinky or dry stuff like lavender they (supposedly) don't like around the plants I can't cover up well. But the most effective strategy - by far - has been my weeding tool. I go around and simply split all slugs I see in half and do it every day and especially when it rains. Others around me are drowning in snails this spring - I have very little in comparison. Another thing I do is to collect all large snails (Weinbergschnecken) and put them out in strategic places where slugs lay their eggs. Snails eat their eggs. Or so the AI tells me 😅