My thought. I think it's a mistake to dedicate time and debut in Japan at this particular time. Just focus on the main comeback. There are many competitors from the 4th Gent for SM to ignore and side track aespa with a Japanese debut. One wrong move could be costly.
The market for kpop GG there is non existent. Just look at Red Velvet or any GG recent releases. Even Niziu did not do much. Although aespa is more popular in Japan than Red Velvet, but I don't think it will make any dent there. Beside, I feel like Japanese love kpop because it's kpop not because kpop song have to be inJapanese language. Just look at IVE and Kep1er, their songs chart pretty high on Japanese chart.
Kpop is even more global now, so dedicate time on the Japanese market does not make any sense because you will limit your songs to a Japanese market. Just look at Niziu for example, once their songs did not do well in japan, they did not have any market to fall back on.
This is not the old day when Kara, SNSD and later Twice had some impact in Japan. The current Japanese market is non existent for most kpop especially GG. atleast most Boygroups can still have decent sale there.
SM structure and thinking are still old schools and dinosaur. From handling aespa performance to this.