Whether you want to divide your campaign spend equally across channels or optimize campaign deliverability, we recommend creating separate line items (and associated budgets) for every relevant targeting dimension within your campaign.
Simply select a relevant Product when sending over the Insertion Order for each line item depending on the strategy you want to execute.
Example:
Line item 1 = Gold CTV Product
Line item 2 = Display Retargeting (Web Visitiros)
Line item 3 = Audio Product