They have mapped out the synapse structure, there is no evidence that synapse structure is enough to actually run the brain. If you can run that brain and show it is an accurate representation of a flea brain then you'd have something, but until then I'll believe that the neurons do way more than ML researchers hope they do.
I'm not sure what level of modelling you'd accept, but we appear to be close:
https://pubmed.ncbi.nlm.nih.gov/32880371/
> Mouse brains aren't even on the horizon of what we can do.
I would say that they are "on the horizon", given that the mouse brain connectome has already been published:
https://advances.sciencemag.org/content/6/51/eabb7187