I am afraid I also need to pay 100$ for the license to use certain features because if an app uses them I cannot even compile.

Recently I tried to compile blink[0] without a paid account and failed miserably.

Yes they also did a great job with sidecar which will only work if you at least own a recent mac. Also it does not work with the iPad Air 2 because they decided it is too old. It is the same story again: Apple softly forcing it's customers to upgrade - nice experience...

[0]: https://github.com/blinksh/blink