I got it done, so here is the best advice I can give:

• You may think it’s this one-time task, and then it’ll never get back to that state. Is that really realistic? Might be for some. But more common is that it’s deeply ingrained in the personality. A “decision” to be someone different will not work in that case. Might be subtle and thus undiagnosed mental problems, such as ADHD or trauma, or just habits, “lazyness” etc. Get on that, learn about yourself. Then you can make SLOW progress.
• Hands-on garbage: Don’t fiddle with little bags that you get one by one. Get a bunch of huge garbage bags ready and fill them. No recycling / separation (at least for now; feel free to sort through the bags later, like that’ll happen), just stuff in what is garbage. When something costs less than you make in 10 minutes and is not needed in the next 4 weeks, it’s garbage. Emotional value? Then not; that’s okay to keep in storage boxes somewhere for peace of mind. Instead of getting overwhelmed by the view, just think: I’ll fill this bag now.
• Hands-on boxing: Get several big boxes ready, don’t pick them up one by one. Fill with everything that you want to keep (for good reasons), but don’t need in the next 14 days. E. g. hair clipper, waffle maker, paperwork. Don’t get too caught up on sorting. Sometimes, it’s best to just fill the boxes. Tax forms from 2023 along with the waffle maker and birth certificate etc. Possibly label by “finding location”, which is fast and surprisingly helpful! But if it’s no hold-up, better to sort a little bit, e. g. boxes of “anything paper”, “electronics, cables and devices” etc.
• Hands-on means: Don’t pick up a box, realise that it has two home-baked cookies from Christmas in it and then wuss around with it through the apartment. Grab and stash.
• When the task is overwhelming, do something, and never underestimate the value of doing a little. For example, you are tired and didn’t get as much done as you wanted. It’s tempting to put it off until tomorrow. But instead, get a bag and fill it with garbage, then sleep with a clean conscience.