I would start boxing up and taking things to salvation army or donating them somewhere. Clutter makes me feel the same way. Yikes. If it's uncomfortable to part with things, just start out small and keep working on it.

I've been on a declutter mission for a while now. Minimizing a bit.

I am going through excess stuff right now too. I get a few boxes from a local grocery store (free) when I shop. I’ve been keeping 2-3 boxes in view and as I do things through the day, I gather items that are no longer needed or wanted and put in a box. Once full, I take to a local donation center.
I’ve used this approach several times over the years and it works for me.

When the trash is picked up I would pick up a few things u really don't care for and trash them