1. We still don't know what the memory engrams truly are ( https://en.m.wikipedia.org/wiki/Engram_(neuropsychology) ). I once read that aside from relying on the interconnections of the neurons they also rely on specific proteins created during memory creation. They are then vital for memory recollection.
2. We know that the connections between neurons are important but we just realized that the support cells (glia) also affect the firing mecanism: they are not only support but a filter as well ( https://en.m.wikipedia.org/wiki/Glia )
3. Inhibitory interneurons provide a way for synchronous firing of neurons to form a learning experience: https://www.nature.com/articles/s41467-019-13170-w
All in all to replicate the brain functionality we would need to fully replicate the chemical composition of the brain to the lowest level (molecules).
I'm not holding my breath.