How to update an Airtable record with an array

What are you trying to achieve?

Hello,
I’m building a Make scenario that:

Iterates over a list of items

Calls Placid to generate an image for each item

Aggregates all resulting image URLs

Updates a single Airtable record’s Attachments field once, with the full list of URLs in one go

My goal is to avoid N separate updates that overwrite each other, and instead perform exactly one update containing the complete array of images.

Steps taken so far

Used Array aggregator with Group by = 1 to force a single group

Tried the (now-missing) “Emit once” / “Commit aggregated bundles” advanced setting

Try with commit aggregator but impossible to find

Switched to an HTTP—Patch request against the Airtable API, supplying records:[{id:,fields:{…}}]

Built auxiliary variables (allURLs, totalCount) plus a Router to fire the update only on the last iteration

Mapped both Field Name and Field ID into the JSON body

The “Update a record” action is executing successfully each time, but instead of appending each new image to the Attachments field, it completely replaces the previous file with the newest one (the operation 2 replace the operation 1).
As a result, after the scenario runs through all of my items, Airtable only contains the last image generated, rather than the full set of images.

I can give you everything you want but i need this solve (24h on it lol)

Thank you in advance

Screenshots: scenario setup, module configuration, errors