Oh OP I feel for you. And I totally understand the “this is not the life I signed up for”.
Just so you know I understand, my 24 year old daughter died, unexpectedly in October last year. I have a 21 year old daughter and a 14 year old son. I have to carry on for them. But it’s very hard. I’m not making this about me. But I wanted you to know that I totally get the “this is not what I signed up for”
I am also am a lawyer (a barrister actually, so I am self employed and the main breadwinner, so money is an issue too)
These are the things that are keeping me (relatively) sane and just about alive:
Candles. Lots of them (I have them arranged around photos of DD but they are lovely anyway). I buy prices tapered candles from Amazon. A big box for £20.
Fresh flowers a couple of times a week. Just a few. I have taken up flower arranging. DD would howl with laughter at that!
A hot scented bath each evening followed by a really nice body lotion. This is my daily treat. Along with 2 Kennedys chocolates and a cup of Lapsang tea.
A weekly splurge on Vinted (Friday evenings). I allow myself up to about £15. Sometimes I go over!
Re-reading my favourite novels as it takes less concentration. For me it is Dickens and Hardy. And Undermilk Wood.
Can’t listen to music. But I think if I wasn’t bereaved that would be a regular go to. I used to listen to baroque music and opera.
Growing things in pots.
Baking for the children.
Keeling a diary.
I am having therapy. That might help you too (I know it’s a cost issue though).
Sitting in the garden after dark with a hot drink wrapped in a blanket.
Nice bedding.
I also know how exhausting it is supporting children with mental health difficulties and neuro divergence. Some of the things I do might be things your children could join you in (Kennedys chocolates - you choose them individually so that’s fun, or getting into speciality tea and choosing it and trying it out).
For me it’s about regular little treats (I’m not going out at the moment or eating solid food - other than the odd bit of chocolate) that can find me at home. Your horizons are obviously wider than mine but hopefully you can take some inspiration from the little things I do.
Sending good wishes and hope.