I nearly transferred to Taiwan a few years ago, and was really looking forward to it.
Everything familiar to a HongKonger but sooo much bigger and better.
Your right about locals not knowing their city. My first Cantonese girlfriend had never been to ClearWaterBay (where I lived), and she was 18. After a few years camping/hiking with me, she was the expert on HK amongst her friends.
Even my Tai Long Wan Guru (the shopkeeper) from years ago, knew only his small patch of the woods. Sai Kung town once a week and Central once a year.
For 400km2 that’s pretty scary.
Ahh, I still dream of Taiwan, so much more to explore.