Prime Minister Kiichi Miyazawa: "What we should not forget about relationship between our nation and your nation is a fact that there was a certain period in the thousands of years of our company when we were the victimizer and you were the victim. I would like to once again express a heartfelt remorse and apology for the unbearable suffering and sorrow that you experienced during this period because of our nation's act." Recently the issue of the so-called 'wartime comfort women' is being brought up. I think that incidents like this are seriously heartbreaking, and I am truly sorry”. [0] Just one quote I grabbed from a long list of apologies listed on Wikipedia.
Also, Japan has paid reparations, multiple times with Korea agreeing each time it settled the matter. “Under the agreement, Korea received $300 million from Japan, as full and final settlement for claims between states, claims between one state and the individuals of the other, and claims among the individuals of the states, including those specified in Article IV (a) of the 1951 San Francisco Peace Treaty. Private companies were also considered individuals for the purposes of the agreement.” [1]
There are certainly nationalists in Japan who didn’t want to apologize or pay reparations, but most of the population does recognize it and feel remorse, and the government has also officially apologized and paid.
At this point, there’s nothing Japan can do since stoking hatred of Japan is a political golden goose in Korea and no amount of apologies or reparations will ever be enough until Korean sentiment shifts and it doesn’t score so many political points at home.
[0] https://en.wikipedia.org/wiki/List_of_war_apology_statements...
[1] https://thediplomat.com/2020/10/the-japan-korea-dispute-over...