Update: I got it working. After reinstalling all mods, I merged all of the texture mods together (ModCiriLoreFriendlyFull, modGeraltChestHair, modGeraltHWwhiteBeard, modGerskinHoS, modGerSkinNoHair, modHDReworkedProject, modNoDirtyLensEffect, modNoScreenWaterDrops, modOrnamentedKnife, modToxicityCleanFaceAndScreen, and modWitchereye), not just the 8 mentioned in that section of the STEP guide. I can now set TextureMemoryBudget to 4000 and play the game smoothly. Setting it to 4096 still gives me missing textures.