If I understood your situation correctly, you’re using the calendar plugin to create future daily notes and want to do date math relative to that daily note. You can do this in Templater with the date.now function.
<% tp.date.now(“YYYY-MM-DD”, -1, tp.file.title, “YYYY-MM-DD_ddd”) %>
So, what this function does is output date in YYYY-MM-DD format by looking at the note title (I believe) which is in the YYYY-MM-DD_ddd format. The -1 gives you the prior day (e.g. for daily note 2021-09-21_Tue this will output 2021-09-20). You should be able to change the date formats in both places as you please as long as you capture the month, day, and year in the note title. You can change the offet to whatever you need: -1 for the day before, 0 for that day, 1 for the day after, etc.
You can have this output week numbers using the ww date format, but I couldn’t find a simple way to do date math based purely on future weekly notes.