Filing Single

I recently divorced, no dependents. I know I need to change my filing status to single/married filing separately. To make sure enough is taken out of my paycheck, I should claim zero correct? I also have a little extra taken out of my paycheck just in case I may owe at the end of the year. 

 

The second part to my question is that when filing for 2022, I need to file single on my tax return, but in doing so that is for the whole year correct vs. just when the divorce is final?  If I changed my status to single mid way through the year, will that cause me to owe more because the first part of the year I was married?