Power Automate Custom Connector Authorization Header

I am trying to make a custom connector in Power Automate with an API that I have used before with Powershell. The issue is that the one parameter I need in the header is Authorization, which is not allowed by Microsoft for some reason. I have found several forums online about how to get around it, but nothing has worked. Here are some forums with potential solutions:

https://powerusers.microsoft.com/t5/Microsoft-Dataverse/Authorization-header-is-not-allowed-Use-API-Key-authentication/m-p/894511#M10780

https://powerusers.microsoft.com/t5/Connector-Development/Authorization-header-using-HTTP-via-on-premise-datagateway/m-p/1339127

I am running into the same error message when trying to create a header with Authorization in my header:

'Authorization' header is not allowed. Use 'API Key' authentication type in the Security tab to set this header.

Here are my settings. The Authorization parameter should have a string value of "rest_api_key=xxxxxxxxxxx"

Despite me overriding the header, the actual request header in my connection looks like this. The token is a random string that is very long, so I have shortened it for simplicity.

{"Authorization": "Bearer eyJ0eXAiOiJKV1...."}

When I actually go to make a connection I am entering the full value "rest_api_key=xxxxxx" as the Authentication parameter.

Has anybody else run into this issue when trying to set a header of Authorization?