I don't think it'll happen that way. One yes, maybe two - this makes total sense on several levels including access to US military industry, political / economic ties with the US strengthening as a firewall vs China, having a secure and stable location to conduct business and retain capability in the event of a military conflict or even natural disaster (Taiwan has 9 volcanos and sits near a subduction zone making it susceptible to earthquakes and volcanic eruptions).
But 5? No.
My guess is they'll have one gigafab with 7nm / 5nm nodes, maybe some 3nm capacity, and the rest of their future processes will be done via upgrades to existing nodes in Taiwan. I think they will keep the bulk of their production capacity in Taiwan, with AZ as a hedge vs the unforeseen.