As I understand the changelog, items from disabled feature toggles are not meant to be obtainable in worlds without that feature toggle active. But saved hotbars can do it.
1. Create a world with the 1.20 features enabled.
2. Get a camel spawn egg.
3. Save it in one of the saved hotbars.
4. Enter a world without the 1.20 features.
5. Load that hotbar.
- relates to
MC-258283 Monster spawners with disabled mobs do not display the "disabled item" word