The following is a quick guide on how to make other start menu background replacers compatible with Skyrim Anniversary Edition:

1. Go to your Skyrim SE folder and navigate through data -> meshes -> interface -> logo
1a. If using Mod Organizer, simply open the background replacer mod folder and go through meshes -> interface -> logo
2. Right click the logo.nif file and copy it.
3. Paste it into the same folder. You should now have two files; "logo.nif" and "logo - Copy.nif"
4. Right-click and rename "logo - Copy.nif" to "logo01ae.nif"
5. Done!