A .app bundle is not an executable, it is a folder with a specific structure. The executable code is in the bundle's Contents/MacOS directory. You don't want to add anything to that.
You could put the symbol file into the bundle you distribute to users, but there is really no reason to do so. It is just dead weight to users, it is only useful to you. If you really want to put it into the bundle, you could copy it to some location in the bundle before signing and notarization. You'd do this by adding a post-build script to the Build Phases of your target in Xcode.
A more reasonable approach is to simply archive the .dSYM files for every release you make, and use the appropriate dSYM when you receive a crash log. You can symbolicate the crash logs by hand or using Xcode. See https://developer.apple.com/documentation/xcode/adding-identifiable-symbol-names-to-a-crash-report