Weekly Vertical Lines in Line Chart

Currently I have a calendar table that show every date of the year and another column telling me what week it is for that year.
Calendar table

I have a multiple dates table that also has many dates with time and another column with the number of people.

The calendar table has a one to many relationship using date to multiple dates.

Currently I am using a line chart to show how many people are on each date and time.

I would like to add vertical lines for every week. I tried adding my week of year column as an x axis constant line but that does not seem to work. Every time i add it under "what field should we base this on?" it stays blank with no value.

Could someone point me in the right direction on how i can do this if possible?

Thank you