I use this dehumidifier: https://www.amazon.com/gp/product/B07MXDRTKJ - however I don't necessarily recommend it. It's worked OK for the last 6 months or so.

When do you take your comforter out of the freezer?

A couple hours before bedtime.

Is it cold when your in bed?

Not really. But again, this is when I was trying to kill them. I no longer do this.

Do you leave the dehumidifier on 24/7?

Yes.