We are still waiting on the DGraph Team to come up with a solution to the backend security concerns with a timeframe. I have posted several posts about it, and have not gotten an answer on their plans yet. There are many posts about this.
Field Level Auth was on the 21.03 Roadmap, and later changed, so I imagine it will be in 21.07.
However, there are some hacks you can do for now (see my above post as well)…
As well as @lambda custom mutations…, or out sourcing the checks with custom resolvers…