Hi Nikolas,
You might be pleased to note that promoting these ideas is disallowed on the Forum. See: Frequently asked questions (FAQ) - #18 by faujidoc1 where I think that ‘Anicca doesn’t mean impermanence’ is a reference to those teachings.
Q15 But, But, But… I know about these secret teachings and I want to share them with everyone! They have been hidden for so long!
A : How likely is that? Generally such views blithely reject well-established facts. Ideas that there are ‘Secret Teachings’, ‘Hidden Manuscripts’, ‘conspiracies of the clergy’ etc always turn out to be delusional on close examination. Such views seem like an innocuous theory, but they often aim at creating a nationalist, sectarian fundamentalism.Anyone advocating extremist or conspiracy theory views will be warned, and if they persist, banned. Examples of such views include ‘The Buddha was born in Sri Lanka’, ‘Anicca doesn’t mean impermanence’, ‘The original Pali manuscripts at Aluvihara exist’, ‘Chinese texts are all Mahayana’, ‘Mahayana texts are fake’ etc. We treat views that go against mainstream science such as ‘Climate change is not real’, ‘COVID is just the flu’ etc, in exactly the same way.
Ven Dhammanando wrote a commentary on another Forum that may be of interest to you: https://www.dhammawheel.com/viewtopic.php?f=46&t=26749&p=421520&hilit=dhammanando#p421520