The Delta explanation is bollocks, since that's been around for a very long time now. EVA just miscalculated demand. You're very generous to re-schedule your holiday to follow the airline, rather than change the airline to suit the schedule.
In normal times, EVA is my preferred airline, but they do need to operate flights to get my custom.
In 2020 and 2021, before booking flights, I look at scheduled flight frequency AND then monitor one of the tracking sites, such as FlightRadar24, to make sure the flight I intend to book has a track record of operating.
In the last 7 days, the flight I plan to take has landed 7 times, so 100%.
Those who are reliant on tourism probably regret it already, however the Junta don't seem to care at all about the tourism sector.