Which is the clear coat material? The tiled floor or the ceiling, or both?
With the clear coat, you can set “Use Full Precision UVs” and/or “Use High Precision Tangent Basis” in the mesh editor Build settings (which you posted). First, you need to enable “Use High Precision Normals” in Project Settings > Rendering > GBuffer format (it’s a dropdown list). It enhances various things, one of which is reflections by making them more accurate, from what I’ve read in a tutorial and in the doc pages.
You should also enable Transmission in the Skylight and Directional Light, and enable Affect Translucent Lighting in the Skylight. Those settings have observable connection to clear coat materials. One last suggestion: increase the Skylight cubemap resolution to 256 or 512, as it makes reflections and other rendering aspects more accurate and better quality.