Usually 'in the week' would be followed by some qualifier - in the week before Christmas, in the week following his surgery, etc. During the week can stand alone - I don't drink alcohol during the week; the children are always in bed by 7pm during the week - this is to compare with what happens on weekends or holidays.

Where I grew up 'in the week' was used all the time on its own. So I'd say yes, it can stand on its own and you don't need a qualifier. Maybe a regional thing but I feel pretty confident this holds, at least in the UK. Example sentences might be: I'll see my friend in the week. I have a lot of work to do in the week. 'Everyday' as an adjective is one word, by the way.

I've never heard of "in the week" and during the week alone. In the _______ week of June, there will be an event. (First, second, third & last) During the week _____ , i like to read a book Weekends During the week____ , i head to work Week days

Actually during the week is for "repeated things " and in the week is for general ( not repeated) things. Thank you