horde: I think you'll find that there is very little interest in non-stock Android operating systems in this community – the exception naturally being GrapheneOS. I understand that you are aiming to warn users about this maliciously behaving operating system – although my guess is that there are 0 people on this forum that has ever considered to install it. I personally had never heard of it before reading your post.
On the other hand, your post serves to highlight the large amount of trust that one places in the operating systems that one uses. If the tweets you linked to are correct, this "Elexir Project" is quite obviously behaving maliciously towards users. Furthermore, their website is nicely designed and served to impress with promises of security and privacy, but most of the devices they support are either end of life or lacking proper hardware security. This is probably obvious, but the only non-stock Android operating system that I personally fully trust is GrapheneOS. Even if other non-stock Android operating systems are not directly malicious, most (all?) of them lack the security and privacy features that make up GrapheneOS.