I'm unaware if the Server deployed to Amazon would have different available settings. I'd expect these options should be available.
Try the following at your own risk (as it involves modifying files you shouldnt be touching)
Open the following in a text editor:
C:\Program Files (x86)\ArcGIS\Desktop10.5\bin\ServerTypes.dat
Find the heading that starts with:
Before the terminating
</ServerObjectType> tag for this section, you should have the following which ensures you can upload and enable WPS while publishing.
<Description>WPS Server Object Extension</Description>
Note - this file also exists on the server, but I'm pretty sure its the arcmap version you need to modify.