I know about https://keepandroidopen.org/nl/, but this is only a partial answer to my question. It's still a developer's choice to enforce anything about #Play Store. This needs to be made illegal (if it isn't already), and cases like the #MyCupra one about require a class action lawsuit (IANAL). One way to start this is to name-and-shame application developers who willingly comply with Google's brainwashing schemes. These companies need to be made aware of their wrongdoings; especially non-US ones.