I was cathing up with the project and I found out that Elixir has been chosen as the backend language.
I'm intrigued by this decision as Moodle is a PHP comunity and it seemed the easy path. Sure Elixir has a lot of benefits but I think you are losing a lot of potential Moodle developers doing so...
I also would have added other elements in the decision, as the ActivityPub support on the language. Or before that why ActivityPub has been chosen among others, as it seems a new tecnology, or at least I never heard of it.
Maybe you are taking too much risk chosing new tecnologies when PHP, a REST api and maybe a proven message queue service would be enough to start?
Hope I'm wrong!