Edit creative on Google image and Performance Max campaigns

Today we can replace the creative on a Google search campaign through the top-level headlines / descriptions / finalUrls arrays on PUT /v1/ads/{adId}, and that works well. For Google campaigns with imagery (display and Performance Max) there
is no equivalent: the text can't be changed afterwards and the image can't be replaced at all.

Why it matters to us: we build campaigns for small business owners who don't log into Google Ads themselves. When their ad needs a new photo or a sharper line, the whole point of our tool is that they can do it where they already are. Right
now our only honest answer is "this one you have to do in Google Ads", which is exactly the step they hired a tool to avoid.

What would help, in order of usefulness:
1. Replacing individual assets (an image, a headline) on an existing image or PMax campaign.
2. If replacing in place isn't possible, an endpoint that swaps the whole asset set at once, the way the search arrays already work.

Meta and LinkedIn already support both text and image edits after creation, so for us this is the one platform where the flow breaks.