I really struggle with motivation too, and more so now that I'm retired. And of course we've pretty much been always at home for the past year. I know that sounds strange, but I think it's because before, my time at home was limited so I needed to cram a lot of stuff into it. Now it isn't limited in the same way, and there's always tomorrow. Procrastination is my close companion. . .
I make goals. I make lists. Like the OP, I stay with it for a while, then - boom. Habit gone. I have James Clear's book Atomic Habits. I like it. I just don't DO it. So far the only habit that's stuck is weighing myself daily. We have greatly increased our fruit and veggy intake, and watch our carb intake. My daily weigh-in keeps my food intake more conscious, and I've lost 20 pounds without dieting or feeling deprived, since March. So why can't I use those same thought processes to make progress on my house??