Hi @Alessandraf,
Welcome to the Affinity Forums
Affinity Photo for iPad supports both the Apple Core RAW engine, as well as the Serif Labs RAW engine so it will depend on which engine is in use, and on which platform as this may cause differences in the way your RAW files are displayed between iPad and macOS.
RAW engine choice on macOS:
With the Affinity app open, navigate to Affinity Photo 2 > Preferences > Assistant and select Develop Assistant... in this dialog.
RAW engine choice on iPadOS:
When in the Home Screen of the Affinity app, tap Preferences at the bottom left, from the General tab, tap Assistant Options.
Please ensure that both platforms are using the same RAW engine. Can you also please confirm, what specific camera model are you using for RAW files in Affinity?