You might need to use the generic “Make an API call” with POST method with additional custom fields details mentioned here:
- javascript - Populate ACF Fields using Wordpress Rest API JS - Stack Overflow
- https://community.zapier.com/code-webhooks-52/post-to-acf-fields-using-zapier-wordpress-api-27778
e.g.:
{
"acf": {
"field_slug": "value",
"field_slug2": "value",
"field_slug3": "value"
},
}