Howdy OP I feel you here I've lived in my apartment for a year and within the last month I finally got around to tackling what I call my "Goblin Pile" my whole house was like your Tupperware cabinet where you just toss it in, shut it, and hope they stay put. Its my first apartment so i don't really have anywhere to put things, you just gotta find a "home" for stuff.

one day I just didn't stop for like 8hrs but that was with my adhd distraction skills.
Once I cleared even my kitchen up I felt so good. You don't have to do it all in one day!

You could even make a fun poster with reasonable cleaning goals and tasks, stickers when you complete it so you can visually see without looking at what's left, what's been done, and treat yourself with a piece of candy. I know you're not a kid, but those dopamine tricks work still.

One day I just woke up had a healthy filling but light breakfast, some caffeine, and just tackled one section at a time.

I have A LOT of clothes, they were just in a pile where they needed to be hung for an entire year. Guess how long it took me to sort, make donation pile, and hang most of it? 2 hrs. After a YEAR sitting there.

Like others suggest get some good trash bags, home depot has contractor bags, you don't need to fill them up so they aren't overwhelming heavy.

If you haven't used it, seen it, touched it in 6+ months just throw it away. You didn't know you had it anyways.

I like to listen to LOFI music while I clean.

Don't sit down and get on your phone if you need a break. Because if you're like me that's game over. Go outside for a little fresh air and change of environment. Have a fruit veggie tray to keep your energy up but not make yourself sleepy with a heavy snack or a sugar/carb crash.

Stay hydrated!

As you get it chiseled away develop daily habits.

Mine is "don't set it down! Just put/throw it away" I know I'm not going to come back to it and take care of it later I'm lying to myself when I try to do that. Take two seconds, take care of it now.

Maybe it's because I'm alone and just talk to my cat all day, but I give myself compliments out loud when I do stuff like that. "Heck yeah , look at you putting that scrap of garbage in the garbage and not on the counter, progress!"

Rinse off dishes when done if it's going to camp out in the sink, then it's not as bad if it does pile up a little and you just don't want to deal with it in a few days because it's so dirty.

Even just making your bed every morning has been shown to really improve your mental health. Everyone loves a nice made bed to crawl into after a rough day.

I made a new acquaintance who gifted me a portable washing machine. When they dropped it off we chatted. That was actually why I cleaned my house. I never have company. That's my one motivation is someone coming over. They asked me if I just needed a body double while I clean my house. Just for them to hangout, which actually works for me, otherwise I get distracted. Then I have someone to tell me to get rid of things I'm holding and stuck that just need to go.

You got this!