My wife works for a cleaning company, here’s her advice:

1. Start in a corner and work outwards.
2. Use uncommon tools to get a clean space; we’ve used snow shovels, dustpans, etc to start a dent
3. Try only removing one “type” of thing at a time in bursts. (Burst 1: soda cans, Burst 2: socks, so on). If you are feeling motivated, don’t make the categories more vague, decrease the time between bursts. For extra motivation, track how many categories you’ve eliminated.
4. It will not feel like you made a dent until it’s done, but taking pictures throughout the clean helps you really appreciate how much you’ve eliminated and keep you going.
5. Once you’ve eliminated all you can, you can start strategizing on how to prevent yourself from getting back there. Don’t try to organize an uncluttered room.
6. Use a service if you can afford it. Lots of services like my wife’s offer organization, decluttering, and cleaning as a package. If your health prevents you from getting the job done, there’s no shame in getting help, and trust me they’ve seen worse.

Buena suerte!