This is a video of how to send it with the “Form” data, not the “simple list” data… i know how to do it with the Form… Do you know how to send it with the Simple list data?
The “Listify” component by @knight (Adalomatic) may be your solution. It can combine all items from a list into a text field, which you can then use in your custom actions. It’s a paid component. https://components.adalomatic.com/
Just put the custom action on the list. Then you can reference the fields from that record along with any logged in user fields.
If you want to send an array of those records then @Flawless has given you a solution. You could also go with a query to the Adalo API for that collection, via Zapier or other third party.