One of the challenges I faced when I first started using SAS was not only passing Macro Variable data into a PROC SQL pass-through, but having it resolve properly if it needed quotes around it. When passing a string like value or date/datetime into a PROC SQL pass-through, it most likely needs to have single quotes around it when it resolves.
I have found the best results when using the %BQUOTE function to accomplish this.
More information on the %BQUOTE function can be found here: https://v8doc.sas.com/sashtml/macro/z4bquote.htm