### 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)

if (multimesh->data_cache.size() > 0 || multimesh->instances == 0) {
		return; 
	}
	ERR_FAIL_COND(multimesh->data_cache.size() > 0);
	
	
	multimesh->data_cache.resize(multimesh->instances * multimesh->stride_cache);
	{
		float *w = multimesh->data_cache.ptrw();
		if (multimesh->buffer_set) {
			Vector<uint8_t> buffer = Utilities::buffer_get_data(GL_ARRAY_BUFFER, multimesh->buffer, multimesh->instances * multimesh->stride_cache * sizeof(float));
			{
				const uint8_t *r = buffer.ptr();
				memcpy(w, r, buffer.size());
			}
		} else {
			memset(w, 0, (size_t)multimesh->instances * multimesh->stride_cache * sizeof(float));
		}
	}
	uint32_t data_cache_dirty_region_count = (multimesh->instances - 1) / MULTIMESH_DIRTY_REGION_SIZE + 1;
	multimesh->data_cache_dirty_regions = memnew_arr(bool, data_cache_dirty_region_count);
	for (uint32_t i = 0; i < data_cache_dirty_region_count; i++) {
		multimesh->data_cache_dirty_regions[i] = false;
	}
	multimesh->data_cache_used_dirty_regions = 0;
}
void MeshStorage::_multimesh_mark_dirty(MultiMesh *multimesh, int p_index, bool p_aabb) {