I don't post here often but I'd like to give you a bit of help.
Sometimes thinking outside of the box is useful.
For all of you who are struggling with FI due to fueling, I have a suggestion to make.
Add port fueling...
There is going to be a lot of conjecture and theories, but from experience with adding port fuel on top of a stock DI vehicle, it works, and works just fine.
Just make sure that you are hitting the back of the valves with your injector. How to do this?
I'd suggest looking into an LY7 Lower intake manifold, it'll likely bolt right up. It'll already have the correct bosses in there, and if the fuel rail doesn't fit with the LLT upper, run the LY7 upper.