Looking for some advice about visiting Taiwan and Passport renewal/application

So I’m 32 and I live in the UK. I half English and half Taiwanese, I have an active British passport and a really old Taiwanese expired passport. I want to go back to Taiwan to visit my grandparents and pretty sure I need to apply for a Overseas passport, however I don’t know if I need a Overseas Compatriot Identity Endorsement of a R.O.C. (TAIWAN) Passport or just a normal passport. I don’t want to get into trouble entering Taiwan as well as be enlisted into the military. Any advice would be highly appreciated

Many thanks,

Matt