Newchick I wish I had some words of wisdom but I am the worst person to advise really. I follow Flylady because it is the best system I have found but I have to be honest and say that I haven't found that it solves everything by any means.
All I can say for sure is that my house (as the last two and a bit weeks have amply demonstrated) would be far worse without Flylady's daily routines and baby-steps.
Like you though, I still have issues with my boudoir and home office and roof and basement. I urgently need to get to grips with proper decluttering and bottoming out because the lack of progress is really dragging me down.
I only work a very few hrs a week and only have 1 child and I still find that I am stuck "maintaining" rather than doing the 15 min decluttering a day in the current zone (although I always intend to). For me, this is largely due to a combination of poor time management; never quite getting to grips with the virtual sahp role I have found myself in, finding housework depressing and lonely, and the challenges of this particular house which is huge and old and has holes in walls and floors and crumbling plaster and consequently has no proper storage so things just swim about ifyswim and we are virtually camping in it. I easily spend 15 mins on Mnset most days or 15 mins watching the telly or baking or sewing or some such which I could spend decluttering though.
For you though, it is not a question of poor time management at all, it is because you are working flat out. I just don't know what the solution is to that. If you work seven days, you work seven days, and I don't think you should beat yourself up for not being able to declutter. There is only a finite amount of time available per week and that's that.
Housework is never-ending anyway. Once you finish one bit you have to repeat immediately or there is always a back log of stuff to do.
I started this thread five or so years ago with several other long-standing fledglings and it took me right up to a few months ago to get to the point where the house was in reasonable enough order for me to start tackling the boudoir and office properly. I have made proper progress over the years and I was ecstatic and thought it would be plain sailing from then on in if I was disciplined and stuck to 15 mins decluttering a day.
Since then though, owing to life events (pretty major ones it has to be said) even the basic routines have slipped back and I need to spend a good bit of time getting it the house right again, then Christmas stuff and other fairly time-consuming changes will be happening to delay matters, and so it goes on.
I don't know what the answer is tbh 
. Sorry, I don't mean to sound so discouraging!
But I do know that Flylady is very good to keep the basics going.
And I like her non-perfectionist/just do a small bit each day philosophy. Even 5 mins a day does make a difference.
I know others on here have had success Kondo-ing their entire house in order to declutter and then using Flylady to maintain. But Kondo-ing I imagine would take a considerable bit of time.
I'll be interested to hear what other fledglings have to say about this. Particularly if someone has stuck assiduously to decluttering 15 mins a day and have succeeded in clearing a previously heavily cluttered room with this method.
In my experience, I think it is particularly hard when you are working from home as the last thing you want to do when you have some free time is spend even more time inside the same space and it is even more difficult ring fence and separate work and and domestic chore time and it all becomes a bit muddled (well it does for me anyway, even with the few hrs I am doing).
My ideal balance was when I was working 3 days outside of the home. I found it much easier to be organised then. When I had spent time away, I looked at the house with new eyes and felt refreshed and ready to do some organising when I got back.
Sorry - that long splurge of a post is not much help is it really - to summarise, for me I think Flylady makes the best of a bad job!
to you though!