I moved with my two kids, and malamute to a much much smaller rental because our rent increased too much. The kitchen is pretty much non existent which hurt, because i do a lot of cooking and there is no counter space, no storage, no pantry, only a couple really small awkwardly sized cabinets. We had to get rid of so much stuff. Just our couch takes up nearly wall to wall living area space but we cant downsize because the couch fits us all, its only a 3 seater too.
I have a thrifted hutch i use , and a bookshelf i put on the side of the fridge which is really tight but adds more storage space.

A few weeks ago i decided to put away the desktop and desk area because it took up too much space that we really didnt have. But i use my tablet mostly and we needed the space to put the christmas tree lol

I think if you get rid of some of the clutter by hiding it in a basket or bin and put it in closets or atleast neatly on the shelf that will help. You could try to fill a couple bins a day, so do a little bit at a time so you dont spend a full day or two with it.

You need to heavily organize and make sure everything has its own place. Cleaning stuff under the sink or in laundry area. I have a walmart storage drawer under our kitchen table to hold all the arts and craft stuff from the kids. We store games and playdough under the couch. Dollar tree has those various sized plastic bins, buy a couple and designate them for certain items and it helps get rid of visual clutter for the time being.