### Godot version

v4.2.beta1.official [b1371806a]

### System information

Ubuntu 22.04.3 LTS 22.04 - X11 - GLES3 (Compatibility) - AMD Radeon RX 560 Series (polaris11, LLVM 15.0.7, DRM 3.42, 5.15.0-88-generic) () - AMD Ryzen 3 1200 Quad-Core Processor (4 Threads)

### Issue description

![image](https://github.com/godotengine/godot/assets/1330325/7a986599-5a68-42a4-beb1-5d3b4bf7db6b)
![image](https://github.com/godotengine/godot/assets/1330325/e8b8546b-b47b-4add-9567-7f70709ab03c)

Culling 3D goes bellow 60 fps even with just about 50 simple animated models. With v4.2.dev6.official [57a6813bb] many more models can be spawned without fps drop. However, both versions do show high cpu usage for culling 3D. Without animations there's barely any usage.

### Steps to reproduce

Spawn models with animation with the Compatibility renderer.

### Minimal reproduction project

[CullMRP.zip](https://github.com/godotengine/godot/files/13400514/CullMRP.zip)

MultiMesh *multimesh = multimesh_owner.get_or_null(p_multimesh);
	ERR_FAIL_NULL(multimesh);
	ERR_FAIL_INDEX(p_index, multimesh->instances);
	ERR_FAIL_COND(!multimesh->uses_custom_data);
	_multimesh_make_local(multimesh);
	{
		float *w = multimesh->data_cache.ptrw();
		float *dataptr = w + p_index * multimesh->stride_cache + multimesh->custom_data_offset_cache;
		uint16_t val[4] = { Math::make_half_float(p_color.r), Math::make_half_float(p_color.g), Math::make_half_float(p_color.b), Math::make_half_float(p_color.a) };
		memcpy(dataptr, val, 2 * 4);
	}
	_multimesh_mark_dirty(multimesh, p_index, false);
}
RID MeshStorage::multimesh_get_mesh(RID p_multimesh) const {
	MultiMesh *multimesh = multimesh_owner.get_or_null(p_multimesh);
	ERR_FAIL_NULL_V(multimesh, RID());
	return multimesh->mesh;
}
AABB MeshStorage::multimesh_get_aabb(RID p_multimesh) const {
	MultiMesh *multimesh = multimesh_owner.get_or_null(p_multimesh);
	ERR_FAIL_NULL_V(multimesh, AABB());
	if (multimesh->aabb_dirty) {
		const_cast<MeshStorage *>(this)->_update_dirty_multimeshes();
	}
	return multimesh->aabb;
}
Transform3D MeshStorage::multimesh_instance_get_transform(RID p_multimesh, int p_index) const {