Hi @sebgedge ,
Could you please share more detail with your SQL database?
Set the primary key is the first essential condition to perform CRUD with SQL in PowerApps.
You also need to check if you have defined a Trigger within your SQL Table. If you defined a Trigger within your SQL Table, the Insert and update operation from PowerApps app to your table does not work. Please consider remove the Trigger from your SQL Table, then re-create a new connection to your SQL Table from your app, check if the issue is solved.
If you have set the primary key and removed the trigger, you need to delete the SQL connection and re-create a new connection to your SQL Table from your app, then check if the issue is solved.
Reference: Known issues and limitations of SQL server
If the issue still exists, please consider remove the SQL Table from your Azure SQL, then re-create a new one, re-create a new app based on the new created SQL Table, check if the issue is solved.
Note: It takes a while for changes to SQL to be reflected in PowerApps, please be patient.
Best regards,
Sik