SharePoint List: Conditional Formatting on Date field using calculation or calculated column

Hi, I am a novice and hoping someone can help me out. First thing, I am not good with any code languages so please be kind in your responses 🙂

I have a SharePoint list which has a date column called "Doc Request Date":

• I need this date column to highlight to alert the user if the document sent has expired.
• Documents expire 35 calendar days after the Doc Request Date.
• Additionally, there is a date complete column, which if containing a date, means the issue is closed and therefore no alerts are required. 

What I would ideally like:

• If "Doc Request Date"  +35 days is before today and "Complete Date" is empty, then background green
• If "Doc Request Date" +35 days is equal to today and "Complete Date" is empty, then background yellow
• If "Doc Request Date" +35 days  is after today and "Complete Date" is empty, then background red
• If "Complete Date" has a value, then "Doc Request Date" background is white

How would I go about doing this? Is it possible? I tried creating a few calculated columns to base the conditional formatting on before I realised that the conditional formatting doesn't work for calculated columns! I think I need to do this in the advanced JSON editor, but like I said, I am useless at any form of code language. ANY help would be greatly appreciated!!