There is no support for removing the UI requested currently.
The alternate UX option you used so far to remove BG could be expanded upon to include the additional steps.
We can do a custom programming on our end to add another alternate UX for your use case, called something like “image-upload-only”, however that will require you to either upgrade your license to Managed and use the included dev time (5 hrs), or upgrade to Standard License (1 hr) and add on any custom development time as needed. The development project to remove those steps, buttons and add support for the new alternate UX, test and push to production and test some more, is estimated to be 2-5 hrs.
Also keep in mind that the text and free graphics are used FREQUENTLY by people who purchase canvases on other sites. These are generally good for conversion and aid in providing a way for customers to very easily personalize in ways that they can’t do otherwise. I would test the app with all features and see what sales come through before removing what might be the main sales driver for your users compared to other sites that only have image-upload.