According to a recent TECO notice I found , ROC passport holders can enter Taiwan on an expired passport up until 6 months after expiration date (relevant text below). The notice advises the reader to double check with the airline, presumably to make sure they’ll let you on with an expired passport.
Has anyone done this, and if so, were there any problems or complications you encountered on either side of the flight?
“中華民國護照即使已過期，但還在過期後6個月之内，持照人依然可以自美國境內搭乘直飛台灣各國際機場班機返國，惟於出發前，仍宜先向航空公司確認。”
Airlines are notorious for telling you one thing when you call them and another thing when you’re checking in. So make sure you get anything they tell you in writing, stamped and signed by the CEO.
Basically you can enter your home country on an expired passport any time. You don’t even need a passport in the EU, just your national ID card. And when arriving in Taiwan if you have e-gate access you can just scan your ID or APRC. No need for a passport.
Since COVID stared the e Gate system is off. At least every time I am at the airport.