I am creating a flow to take a file uploaded to Microsoft Forms and move the file to SharePoint.
As the file is moved to sharepoint, it will be renamed using the answers on the form where the file was uploaded.
I am able to move and rename the file using the answers but I am stuck when I try to add the file extension on the end, as it may be a different file type depending on the uploaded file.
So far it goes like this:

When a new response is submitted:
Form id: (Selected form)
Get Response Details:
Form id: (Selected form)
Response ID: Response Id (dynamic content)
List files in folder(OneDrive):
/Apps/Microsoft Forms/(Selected form)/Upload
At this point I was going to use an Apply to each to take the Value from the OneDrive file and use 'Compose' step to take the input Name(OneDrive) and have it output the name. Then 'Compose 2' step to separate the name from the extension and leave me with just the extension to use later on.

Compose:
Input: Name(OneDrive)
Compose 2:
input: Expression: last(split(triggerOutputs()?['body/Name'], '.')) <-----this expression doesn't properly output anything
The extension would be used when creating the file name in the next part

Apply to each:
(select an output from previous steps)
Value(OneDrive)
Get File content:
File: Id(OneDrive)
Create File:
Site Address: (Sharepoint site)
Folder path: (folder location where the file will be dropped)
File name: (Form Answer1)-(Answer 2).(output Compose2) <--- this is where the issue is
File Content: Body(OneDrive)
Delete File:
File: Id(OneDrive)
I originally added the "Media Type(OneDrive)" Dynamic content but it returns the type of media and extension.
Example: .application_pdf