Loading a Ray Tracing pack with sufficient RAM and VRAM still gives the error:

Resource Pack Fallback

Low memory. Textures will have a reduced level of detail.

Steps to reproduce:

1. Load up either the latest stable or beta of the game. I've reproduced the same error on both.

2. Find a high resolution resource pack (in my case, I'm using: VanillaRTX By Xubeir) and install it

3. Load the pack, turn on Raytracing and load up a world or realm.

4. You should see the error pop up on the top screen.