My statement was a response to their employee's comment about the downsides of Postgres, which I quoted. I didn't say what avoiding Postgres is bad, 1. I quoted their unbacked comment, and then 2. I explained it is not bad to use Postgres and actually it's worse to roll your own database. Not sure where you got the fact they use Redis and Maria, that is not very clear on their website, but I found an article on Github: https://github.com/appwrite/appwrite/blob/master/CONTRIBUTIN...
It's much easier to understand Supabase (they use Postgres) vs. AppWrite (I could not find out what they use). They did mention their "new database: completely rewrote the Appwrite data management layer". https://medium.com/appwrite-io/everything-you-need-to-know-a...