About the error “Bad Request”, from the error message it seems that you didn’t enter valid values to the list. What was the value you entered?
What are the column types in your list? Please share more details about the SharePoint list. I will try to reprodcue this issue on my side.
Please check this documentation about troubleshooting a flow for a reference. Flows fail if a setting in an action of the flow doesn't function as expected. In this case, the error message contains Bad request or Not found, or an error code of 400 or 404 appears: