Suspected ASD daughter needing more from me, but I just really need a break!

[Heyjumbo]

Struggling with this.
I've just started the ball rolling towards a diagnosis for my daughter who I suspect has ASD and ADHD.
She is very emotional and sensitive at the moment and crying more than usual, Struggling with change more than usual, she's refusing to do things a lot, and expecting a lot and having tantrums if she doesn't get what she wants-shes 7.
She is asking to stay up later than her younger sibling, which I do understand but I'm so drained come 7pm, I just need her to be in her room. She doesn't have to go to sleep until 8.30 and she has access to a TV until 7.30, paper, colouring pencils and books etc. I also read to her and she read to me at some point between 7 and 8.30pm. It's actually really good for her to have this calm, wind down time.
When she does stay up later, she doesn't stop talking- she doesn't switch off and she also has tics so there are a lot of random sounds and fidgeting which is exhausting for me as I can't relax or switch off. She will also spill her drink atleast once a day so I'm often mopping up spillages or she's having to change her pyjamas because she's soaked them accidentally. We can't just relax and watch a bit of TV. I have underlying health issues myself so I really need this time to switch off and re-energise. Her Dad (my partner) is also going through a diagnosis so it's coming at me from two sides. If I'm honest, I'm totally fed up of dealing with these traits and behaviours single handedly with little support.

Having to help and manage his behaviour on top of hers is exhausting, particularly with my own health needs. He is also not helping much with her issues.
BUT I feel like I'm letting her down when she clearly needs more from me. I have a young toddler also who runs me ragged and needs me to sit with him each night until he falls asleep. It means I'm in demand and she is often not getting what she needs. My partner doesn't get it. Just says she should go to bed when we say and has no empathy or appreciation for her needs.
I let her stay up last night and she split her drink all over the sofa- we couldn't continue sitting on it as she didn't retrieve the cup quickly enough and I shouted at her and made her cry. I instantly regretted it, but I don't know how to manage better without just getting the children to bed as early as is possible.
Help?

Put the drinks in a sports drinks bottle for a start. Or don't give a drink after x time at night.
About the bedtime, can you compromise? She can stay up til 7.30pm, after that in her room but you'll come read to her/listen to her/talk to her about her day/worries etc for half an hour. Some special time for the both of you?

Is your partner your son's father? Can he not do his bedtime?

If you invest in making your dd less stressed that may actually make your life easier.

Try to readjust your expectations of what she should be able to do by this age, some pragmatic adjustments may help you both reduce the sense of pressure. My DS is ASC and also DCD, he spills things left right and centre, I completely feel your pain and frustration over it, but my DS can't help it, in this area he is developmentally at a younger stage. We use a sports bottle with a leak proof straw (Camelbak, also brilliant for helping with regulation as sucking hard through the straw gives proprioceotive input). And for drinks like milk, we use a Keep Cup with a tight fitting lid.

It sounds like you're carrying a lot and want your partner to help more. Have you thought about counselling specifically for couples where one partner is autistic?