It smells like a few members already pointed out, the March update.
I've seen websites, old and new having 0 problems indexing but on the other side, they are not ranking.
And vice versa, like, I bought a new domain 3 days ago, and published 2 articles, they are already not just indexed but also ranking.
My 2 cents: Doing news sites in this period is a bad decision, especially if you need to publish 10, 20, or 30 posts daily, it just won't work.
I would stop losing my precious time, focus on other things that work out, and follow the situation closely.