There is a visual bug when using either Iris or Oculus when flywheel's backend is set to "batched" and shaders are enabled. The issue leaves once flywheel is set to instanced or turned off. This is only apparent when this mod is added. Entities also tend to "flicker". I have encountered this issue on both Fabric and Forge using the latest version. Only other thing I can think of is that I am using Nvidium and BSL Shaders (MC. 1.20.1).

Do not use "batched"; instead, use "Instanced". Batched is not supported, and Instanced has better performance. There is no reason to use Batched.