How can I get myself to go outside?

I'm reassured you're with a therapist, whom will be the best source of help in working through this.
If this stems from a traumatic event, it will be a gradual - protracted approach, in regaining the ability to leave your home, and find meaning in life again. In baby steps, your therapist will walk with you.
Depression after a loss or a fundamental change in life, is expected, and can impact us significantly .
Continue to keep your therapist in the loop on what initiatives are working, and any changes you feel are needed.
Lean on your friends here and at home, for strength and support. Continue talking to us.
God bless.

Could be the meds doing that. Most meds for mental stuff and depression makes a person even more depressed or even suicidal. My friend also experienced this. He cut the pill in half and it helped. Or just stop taking it altogether. I'm sure that's what it is. But other than that it's possible a demon has crept in you and that's the blockage. There are different demons that will affect a person in different ways. I've experienced 2 different kinds. One that makes you mean, one that makes you not feel the beauty in nature anymore. It's like it puts a shield over your soul. Normally the main ways a demon will want to possess you is from drug or alcohol use, or extreme sinful behavior like sex. But it's usually from drugs. Even a one time drug use. If you tried a drug only one night, and never touched it again, it could be from that, but I'm guessing it could be the new meds. If you think you have a demon. Ask me how I got rid of mine, it's very easy.

I can relate.
Don't listen to your mind. Don't think.
Just get up and go out. 5 minutes.
Then increase the duration day by day.

Or ask a friend or someone who goes out, tell them to come along or call you everyday before coming to your place, so it will become a sort of obligation to be ready when they come.

I'm deeply concerned about what you're describing. It sounds like you may be experiencing symptoms of depression, anxiety, or possibly agoraphobia. The way you're perceiving the outside world - as lifeless, colorless, and threatening - is a significant red flag that suggests your mental health is suffering.

Tell your doctor about this. You may need your meds adjusted.

I've encountered several people who have said the same thing to me. When you look at the time frame you speak of, that time coincides directly with the end of the Covid pandemic. I believe that many people are still in 'Covid' mode where they self-impose a lockdown on themselves and stay indoors because they feel comfort in isolationism.

A friend of mine said that he really liked the pandemic because the subsequent lockdowns that followed gave him the perfect excuse to be antisocial, irrespective of the underlying reason for lockdowns being Covid.

Hard to give advice if we don't know what happened
You should seek someone to talk to ... professional ... unless there's a reason you can't

Idk maybe you need a buddy to go with so you're not alone.. or get a big guard dog?

Sounds like a really tough problem.

what happened

Do you have a job? You can use it as an excuse to get out, trick your mind about it. Unless you work from home.

What happened the last two years to affect you this way if I may ask?

Open the door and go out, even if only 1 step

Get off the drugs, buy a motorcycle.