Custom localBounds for MeshRenderer

I need to override localBounds for a MeshRenderer, just like you can do with SkinnedMeshRenderer. The reason is simple - mesh that's rendered is being deformed by the shader (pretty similar reason why SkinnedMeshRenderer supports it). And no, I don't want to set the mesh bounds - the whole point is to support instancing and render the same mesh with different deformations. What do I need to meet my requirements? Request an unity feature? Write a custom SRP with custom culling? Get full unity source codes? Or is there a solution ready, and I am just not seeing it? - I could just use SkinnedMeshRenderers instead (and just don't use any bones) but that disables instancing by default