Hello Brooke , I'm Vinay here to help you .
I understand that you already tried few settings . I will let you know few other resolutions .
To create a custom print size go to settings - devices and select Printers & scanners -Locate your Canon G5020 printer, click on it, and choose Manage. In the Printing preferences, look for the Page Setup or Paper/Quality tab to find an option related to Paper Size. If a Custom Size button isn't visible, check for options like "User Defined" where you can enter your desired dimensions .
If you are still having issue then you can set a custom page size in Microsoft Word. Open Microsoft Word- go to Layout - Size - More Paper Sizes and enter your dimensions. Also same process in Adobe Acrobat, navigate to File - Page Setup or Print and choose Page Size - Manage Custom Sizes. After creating the custom size, print a test page to ensure it works correctly.
Thank you