I am trying to make a 2024 version of my paladin. I can pick Oath of Devotion because it is free. I can pick the Xanathar’s options and Oathebreaker because they are from 2014 content I own, but I cannot pick the 2014 version of things I own if they’re in 2024 content I don’t own. I can’t use the Oath of the Ancients.
Paper and Pencil might be hard but there’s plenty of free tolls for the math and dice rolling.