I don't often think that quizzes have too much time, but this one does - I basically typed in all of the European countries and still finished with 2:30 to spare.
I third it. I was left with that at the end despite having typed Czechia. On realising that the mystery country bordered both Poland and Germany, I worked out the answer.
I tried to put in Czechia but it didn't work. Then I forfeited the quiz and saw the only red answer was Czech Republic. Please can you accept the shortened version because that is the official name of the country now, and it saves time to finish the rest of the quiz. Other than that, very good quiz.
2. Czechia should be accepted as the input of Czech Republic