basically its 5 years if married, 7 years if not; proof of funds (NT$ 3m if married, NT$ 5m if not - just borrow the money, out it in your bank for 3 days, and you get the necessary certificate). Any crap about having special skills is just that - crap. They just want to see the colour of your money, even if it is borrowed. Then you have to get a police certificate from your original country, one from taiwan.
Oh yes, and you have the minor inconvenience of having to renounce your own citizenship. this means you cannot go overseas for the period you are stateless - I was 8 months in this limbo - and then you have the option of being “grounded” for a further 12 months if you want to get an ID - which you’ll need if you want to go to HK, china or Macau. Cos you can’t go there on your passport.
So waht you actually get is 1. natiaonlity first (in reality its overseas chinese status - i.e. you have a passport), and 2. citizenship only when you get your ID.