idk if i have adhd or i was just raised by and around some people who do but when i feel like i have no sense of routine, i try to pick one singular thing to start doing. Something easy that i enjoy.
if an every day promise to yourself to do something is too much, every other day or once a week is a great place to start. the great thing is, it doesn't even matter what that thing is. it could be to eat breakfast, go on a walk, or do a lil sun salutation when you wake up. then expand on that. ex: eat breakfast every day. then you add stretching before breakfast. then doing the dishes right after. Some ppl call this habit stacking.
Doing these things with people increases your sense of connectedness or accountably too. Having a weekly or monthly event can change the feeling of the whole week leading up to it.
imo the best way to change anything about your life is to focus on what you can add instead of what you need to take away. it shifts the frame of mind from shame to joy :)