Just because you 'should', it doesn't mean you can.
It takes more than 'should' to be able to do something. So, once you've really determined that it's important enough to try to do, even though you doubt your ability to do it, what do you do? How can you turn your shoulds into cans?
—Reduce the scope of the project.
—Identify and address barriers.
—Be willing to look into options that break norms.
Example from my own life: My previously-held-and-never-really-examined unspoken goal of "brush twice daily, flossing after, ideally after eating, with the expectation that I do nothing else at that time, in the bathroom, standing on a cold and hard floor, facing my reflection in the giant mirror, using toothpaste every time" was not achievable for me. But it stayed the goal for a long time. Until I thought about it. My more recent goal of "brush and floss teeth more than I had been, ideally eventually making it a part of my daily life, in support of which I will get regular reminders about it from a trusted friend, add reminders into my daily life, and keep dental hygiene supplies within arms reach of the bed and living room chair" has been far more realistic and achievable.
There was immediate improvement, once I realized I could brush my teeth in bed, if I wanted to. Just kept dental hygiene supplies next to the bed, and could reach out and use them, even brushing without toothpaste if that was all I could manage. And, with support and time (five years so far), I've gotten to the point of brushing with prescription-strength toothpaste almost every day at least once, and flossing any time I feel something between my teeth. I still don't brush in the bathroom in front of the mirror. But I brush, and I don't struggle (much) to remember to do it and then follow through. Because I examined an unspoken goal and spoke into existence a more achievable goal, over and over and over, in many parts of my life these past five years.
Reduce the scope of the project. Narrow things down. You can always expand them again. But just think about the core needs and focus on those for a bit.
Identify and address barriers. That cold bathroom floor could have a thick warm bathmat. Or the mirror could get covered up. Or the location can be changed so that it's not on the cold bathroom floor in front of a mirror.
Enlist support. I tried having my in-home workers remind me of stuff, but there were reliability issues and funding issues and other stuff. So I sought out a volunteer, and they became a good friend (also over these past five years). I get scheduled recurring calls, about an hour each time, a few times a week, where the focus is me, my wants and needs and priorities, and the checklist that I created to help guide me through the calls and make sure that I do important things and make plans for anything from later the same day to any time in the future. I built systems to externalize my working memory in visible, modular ways, as a way to deal with my limited working memory. I sought and created ways to give myself support in doing the things I both felt were important and struggled to do unsupported.
Be willing to look into options that break norms. If I hadn't taken the time to think hey, why do even I need to go into the bathroom to brush my teeth anyway?, I would still be that person who struggled to even brush once or twice a week. If I hadn't asked about prescription strength toothpaste as a way to increase the protection of the brushing that I can manage to get myself to do, I wouldn't have discovered that prescription strength is mildly flavored because you're not supposed to rinse afterward, and the milder flavor also made brushing less of a sensory problem for me (also, with no rinsing, I could just spit into a trash can with some tissues, making it easier to use toothpaste when not in the bathroom). If you could easily do things the 'normal' way, it wouldn't be a struggle for you. But if you can make it not be a struggle by doing it a different way, why not do that rather than struggling to be 'normal'?
Do it in ways that work for you, if it's important to you to get it done.
Anyway, this has been your somewhat irregular executive function boop. I hope you find something helpful in it.