[mtlmtlmtlmtl]

My ADHD is severe enough that medication is more or less necessary to function.

Besides that, I've not had much luck being able to channel the focus medications bring, except one key thing. Take your medication after you get started on whatever you want to accomplish. Once the meds kick in, your attention will often grab onto whatever you happen to be doing, and stay there.

Another huge help is the OHIO principle: Only Handle It Once. Try to catch yourself whenever you think "I'll do it later", and do it right away instead. Maybe give yourself a reward whenever you manage to do this, for some self-conditioning.

As for the situation you mention, there is no shame in asking friends or family for help(to do some of the chores, help you get started). Especially if you ask someone who also has ADHD, they will understand your pain and want to help. Often getting that reset back to normal is the best way to get into better habits.

I find it's much harder to establish better habits when I have a gigantic list of unfinished chores to do.

[briHass]

Todo lists -- real ones written on paper -- help me tons. Everytime I have a 'I should.../I need to...' thought, it goes on the list. Then, when a gap in work occurs, I can pick something interesting on the list. The physical strikethrough on paper is satisfying in a way an electronic record isn't.

My preferred medium for notes and Todo lists is index cards. When I complete the tasks that fit reasonably on a card, it goes in the trash. Something about not wanting my desk littered with cards encourages me to complete them; software lists just grow and are easily forgotten/filed out of sight, or worse, become their own organizational, hyper-focus rabbit hole.