There is a difference between managing and thriving though, isn't there? While there is definitely help out there as PP have mentioned, it would be helpful if your DD - and you - were more prepared too.
I'm another one who thinks that a year out is an excellent idea.
A year out gives you and DD enough time to get your finances in order, and to think about the different options.
A year out would give you time to draw up a to-do list, and to visit different universities. Also, your DD would have her results so less uncertainty for her re acceptance.
It doesn't matter that you weren't organised or didn't know - you do now. Lots of students take a year out. And I think that it could give your DD a bit of time to gain experience and mature. As she strikes out on her own, she's going to have to learn to ask for help, and that's going to be a huge step for her by the sounds of things. A little bit more life experience really would benefit her.
There are lots of online opportunities that your DD could explore if she can't get a physical job (check out the Money Matters section here on MN - in particular the earn £10 per day thread). I pay my mortgage by working online as a copywriter. It's a brilliant option if you're autistic and don't thrive on lots of social contact in a day to day job.
I mean this gently, but your posts seem very absolute, even for things you haven't thoroughly checked out - such as the apprenticeship. Don't dismiss things before you've at least tried to apply. It's good to be realistic but it doesn't hurt to try!
Also, I know you've answered this already but I was someone else who got the distinct impression that you may be neurodivergent yourself. It presents so very differently in women, and especially in those of us who were diagnosed late and have spent a lifetime coping. It's none of my business but it might be useful to you to look at both autism and ADHD in adult females. With a DD who has been formally diagnosed, it's worth considering - especially as you seem quite overwhelmed with fairly straightforward stuff (I'm speaking as someone who also regularly feels overwhelmed by even the most basic things despite being an outwardly professional and confident person!)
For reference, I'm autistic/ADHD and my DC are both diagnosed too. I completely get that it's even more complicated when you have neurodivergent DC, which is why it's helpful to be really prepared before she takes the plunge.