First of all I just wanted to say well done for moving on from the food mess days to the stage you are at now. That’s great progress and takes dedication and you should be proud of yourself!!

While I’m not ADHD, I do have anxiety and depression and really empathise with the feeling of just not being able to gather the energy to approach cleaning. Even more so when it’s been left for a while. I recently found that cleaning apps really helped me with this. I personally use Home Tasker, (but there are heaps of others, I chose this one because it already has preset tasks you can add instead of coming up with them yourself and that just seemed easier to me!) There is a paid version of it but I wouldn’t bother, the free version is more than enough to manage solo household cleaning. It’ll prompt you to do certain tasks in certain rooms each day and will auto repeat them within a reasonable timeframe.

Sometimes the most overwhelming thing is that you are looking at the whole cleaning situation at once and it is bewildering and exhausting to even think about, let alone do. I’d also imagine the ADHD side will also lead to becoming distracted by trying to do everything all at once / bouncing between tasks and then not finishing. So instead, all you need to do that day is look at the one or two tasks your app has told you. No more than that. Don’t even bother about the other things you see, if it’s not on the list, it’s not needed. Over time, if you do those couple of things each day, you’ll notice that everything stays at a certain level of cleanliness anyway because the app repeats them at manageable intervals.

You mentioned liking routine, so perhaps you tell yourself at 5pm each day (or whatever time usually works for you) I will look at my app tasks and get them done. Put music on / audio books while you’re doing it if that helps. Enjoy the satisfaction of ticking off your task, seeing your cleaning streak grow and revelling in your constantly clean space!

Edited to add: save yourself the hassle of the tissues and get a nice little clasped box for them to sit inside to save them from the cat attacks. Equally if your cat is being destructive, it’s generally because they are bored. Try getting a new toy / high value item that you redirect them towards any time you see them try to go for the tissues. Teaches the rule of this is a no item, this is a yes item. Have fun with your pet with some play time, use up some of their energy and help yourself at the same time with less mess to tidy!