GDPR technically does apply to apps, and in fact already covers what you're saying. The principle of "data minimisation" (https://ico.org.uk/for-organisations/guide-to-data-protectio...) means you should only collect the minimum amount of data required for a particular purpose, so in theory an app shouldn't be able to spy on you and call home all the time for the purposes of software licensing when something much less intrusive can suffice. Similarly, there is no valid reason why you should be forced to sign into an account to uninstall a piece of software.
In reality though, the GDPR is not being enforced seriously and the same organization linked above who is writing those guidelines is completely incompetent at actually enforcing them.
You see I would be happy to make GDPR complaint about some apps, but I don't want to lose access to them. I am sure if I started something like this, they would just remove access and some of those apps don't have alternatives.
In reality though, the GDPR is not being enforced seriously and the same organization linked above who is writing those guidelines is completely incompetent at actually enforcing them.