I do not want proprietary software nor I want to depend on black boxes to use a service. So if a bank, a public administration etc demand using proprietary stuf

I do not want proprietary software nor I want to depend on black boxes to use a service. So if a bank, a public administration etc demand using proprietary stuff that does not came from them they force their customers to buy such black boxes and suffer all their limitations. For instance I hate in the same way countries that ask users to install proprietary crappy software's to pay taxes instead simple pdfs/standard WebUI.