I'm sorry OP, this all sounds really hard. School refusal is the pits, but it's nearly always harder for the child who is refusing school than their parent. My son is now 17. He has always hated school (well, he probably just about tolerated primary school, but once he got to secondary school, it got worse), but didn't start refusing to go until he was in year 8. In year 8, he started telling us how much he hated school how all the kids hated him and started being consistently late for school (we live about 200 yards from the school and I think that they bought his excuses about "The traffic being bad" showed their absolute disinterest because if they had bothered to check his records, they would have know than he had about a five minute walk to school).
Eventually, he started refusing to go. At this point, I was becoming more and more sure that he was autistic - he'd never been happy in school and had never really had any friends either - once he started refusing, I started walking to school with him, and waiting in reception to speak to someone about him.
They really didn't care. It was all "He behaves well and gets good marks" - well whoopee do - that's not much use if he actually hates school and is doing anything he can to get out of going - they literally didn't care that he was unhappy.
Eventually, we get to year 9, at which point he told us he wanted to change schools, so we looked into this. The new school couldn't have been more different and wondered at the outset if he could be autistic. Unfortunately, transition was delayed by lockdown and he eventually started the new school in year 10 in the September after the first lockdown.
Anyway, this is going on for ages, but to cut a long story short, he was put on the ASD waiting list, but there was an incident at school where he was assaulted at school and we ended up getting him assessed privately (I realise this isn't possible for you and I just feel so fortunate that we were able to do this). He limped through year 11 on about 60% attendance (it was absolutely horrendous and he had to be coaxed to school every day he went in - and I now feel guilty for making him go in when he was clearly hyper anxious about it, but I didn't know what else to do) and because he's naturally very clever, did well in his GCSEs.
He started sixth form at this school and from day 1, it was obvious it wasn't going to work (I don't blame the school, they had done everything they could to help him, but he just couldn't get past any classes that had the kid who assaulted him in them). We moved him to a local independent school (again, we are very lucky that we can afford this and I understand that most people can't - but actually, It is the LAs responsibility to provide schooling that a child can cope with - even if private) and he's been absolutely fine this year - it's very small school, with many neurodiverse pupils and he just feels like he fits in,
Essentially, it's likely that your dd is neurodiverse and just feels that she cannot go to school, but is unable to articulate this to you, hence the excuse of not being bothered. Please keep fighting for yourself and your dd. I sympathise because I know how massively hard it is, but however hard it us for you, it's probably 10 times worse for her.