Can I violate the instruction during installation?

Is it possible to install the module without the use of composer? By unzipping the repository to /app/code directory?

Hi Stasa

Yes it is possible to install the module without use of composer…Just unzip in app/code/ directory.
and run the setup upgrade command…You can easily run your custom module…

I have upzipped the m2e/Stripe repository into app/code/Dfe/Stripe, also pulled down mage2pro/core into /vendor/ directory, ran setup upgrade. Magento application is working, though when I try to access Stores > Configuration it crashes with:

Fatal error: Call to a member function getHomepage() on null in /var/www/html/devmage/vendor/mage2pro/core/Config/Ext.php on line 25

Any ideas on how to fix this?

You should do EXACTLY as it stated in the instruction, and do not listen to the third-party low quality answers.