Hi,

So you need to make fields editable when the state is 'done' and if the user is in product master group.

declare a boolean field like below in your model, for checking whether the current logged user belongs to  product master group or not.

is_master_user = fields.Boolean(compute='_compute_is_master_user')

def _compute_is_master_user(self):
    for record in self:
        if record.has_group('external id of your product master group'):
            record.is_master_user = True
        else:
            record.is_master_user = False

Then you can give the readonly condition to the required fields like below.

<field name="your_field" attrs="{'readonly': [('state', '=', 'done), ('is_master_user', '=', False)]}"/>

Hope it helps