I think if you can set visibility to hide the choice component based on your prior selection, then it will not be required, even if you have the column set to required.
With some brief testing, it also appears that you can pass a value from the prior screen to write directly to the sheet as a non-editable value using the Columns Values. Then use that auto filled value to set visibility on the choice component. So you could have a column in your item details that indicates whether a choice is needed or not (true/false), and then write to the form response sheet using Columns Values. Then use that value to display the choice component only if needed.