What's the error message?
The record does not exist
I think this should be (Airtable record ID) and not a list.

I think this should be (Airtable record ID) and not a list.

I thought so too, but it only lets me select List of Airtable record ID if I use the Find Records step. I had read somewhere that I didn't need it and when I took it out, then I could select just Airtable record ID, but it returned the same error.
It's looking for the EXACT Record ID. Inserting the list won't work as it won't find a record that's a string.
Use the advanced logic, Repeating Action. You can use the find records step as a list. Then move your update record step into the repeating section. Chang it's Record ID configuration to read from the repeating logic.
Hope this helps.
I thought so too, but it only lets me select List of Airtable record ID if I use the Find Records step. I had read somewhere that I didn't need it and when I took it out, then I could select just Airtable record ID, but it returned the same error.
I mean like this, within the Update records step.

Could you provide screenshots of the relevant tables and talk abit about the business use case here? Understanding what you're trying to do and seeing how your base is set up will be very helpful in troubleshooting