UPDATE:
Just upload the extension's file and the composer file ?
I have an idea for an extension.
Can someone make an extension for admin that has 2file uploaders:
One that says please upload the extension's file.
And the second says please upload the composer's file.
Then it uploads the extension's file to /vendor/ and replaces the composer file with the new one.
There should be update extension too, that replaces the extension's file in that case.
I don't how to create extensions, but I have knowledge in PHP.
If anyone wants to create it or at least teach me how to create extensions?