What do you think of my plan to take PTO, but pretend to go to work to get a length of time to myself with no one bothering me?
We are all allowed to take out paid time off when we need it. You shouldn't lie to your employer about why you need to use your PTO however.
The 3-week PTO would allow me to clear my head and make a decision about whether I should quit my job or not.
Paid time off is available and good to use when you need an mental of physical break from your work. It's normal to take that time and think about if you really want to stay in your position.
I wish it was that easy.
You can tell your boss that you need time off for your mental health. It's your PTO that you've earned and you deserve to use it when you need it. Don't feel guilty about using that time for yourself.