ANSWER:
We belong to Him and He may do whatever He wants without anyone being able to object to that. He can annihilate this entire universe and all those who are in it without anyone being able to object! We are put in duniya to be tested to separate the believers from disbelievers. Those who believe in Allah and submit their will succeed and those who don’t fail this test. It is like asking why do teachers examine students at the end of the year and place tests and finals while they know that a lot of the students will fail! Why do governments build roads while knowing people will have accidents and might die?
https://islamqa.info/en/answers/159301/he-is-asking-why-are-most-of-the-people-on-earth-disbelievers-and-why-does-allah-want-them-to-enter-hell