I had a bit of a chaotic childhood and think I might have ADHD. I have slowly tried to sort of "parent" myself to try to change into a more organised and healthy person, so I'll ramble my advice from that:
Atomic Habits by James Clear really helped to change my mindset. I can't really explain how helpful it was, but trust me, it was. I first listened to it on audible during lockdown 1 (when I was depressed AF). After listening to it, I also downloaded an app called "repeat habit tracker" on my phone which I still use to tick off things. At the moment my "habits" are:
Get at least 7 hours sleep.
Take a multivitamin
30 minutes of exercise (walk, gym, run, swim, cycle)
Drink 1.5 litres of water
Floss my teeth
Evening skincare routine
10 minutes of bedtime yoga (Yoga with Kassandra on YouTube).
It might sound ridiculous to "normal" people, but if I don't have that app to tick stuff off on, I probably wouldn't do it. It's been almost three years since I downloaded the app, and I have updated my habits now and again since then. When I first downloaded it, I was struggling so much in lockdown one that it included things like: brush teeth, have a shower, go for ten minute walk. I don't have to tick off brushing my teeth anymore in the mornings (thank god 🤣), and some other things, like eating a healthy breakfast, have become a natural habit, but other things, I still have to consciously choose to do and need to be prompted to do.
Housework wise, I loosely follow the organised mum method. I'm not a mum (yet) but fell into it when I was looking for a solution to keep on top of stuff. Love it. Love Gemma too, she has a podcast which I find very therapeutic. I'm naturally a very all or nothing type of person when it comes to cleaning; I used to do nothing for weeks and then literally spend all day obsessively cleaning. She advises setting a timer, which I find really helpful, I usually do 15 minutes a day which keeps on top of stuff and stops me going too mad with it on the rare days I feel like cleaning everything 😅.
I decluttered everything in our home very slowly over the lockdowns, and have just about managed to keep it up, but still need to be mindful about stuff we bring into the house. Always have a charity shop bag on the go.
So I've rambled there, but go easy on yourself OP. Change is hard, but it is possible. Best to start small, and for me, having a tidy and clean space makes everything seem a bit more manageable. My advice to get started this week would be:
Decutter your bathroom, it's usually the easiest room to declutter as less sentimental stuff, and the sense of achievement will hopefully give you a bit of motivation. Motivation won't come to you naturally; it comes from doing stuff.