texture group = ui with no mipmaps and never stream is the problem — that combo is meant for textures drawn by umg, not for textures sampled by world meshes. on pc the renderer just samples them and nothing complains, but on consoles the ui group gets accounted in a different pool with different residency rules, and a ui texture used on a static mesh can end up simply not resident — which is exactly the gray squares symptom. the plates working is consistent with that too: a smaller set of textures/materials staying under whatever the console path reserves.
the fix: give those textures a proper 3d group — world (or generic), mipmaps on, never stream off — and let the texture streamer manage residency like every other world texture. if they were set ui/no-mips for sharpness, use the normal world group with a sensible max texture size instead; mips on a tiling wall texture cost almost nothing visually and they are what the console streaming pool expects to exist.
after regrouping, repackage/recheck on xbox — the always-missing set should come back. general rule for the future: in uefn, ui group on anything sampled in world materials is out-of-contract; it can work on pc and then break exactly like this on console, because each platform cooks and pools those differently.