The author has apologized for not updating the WN for 5 months now. https://mypage.syosetu.com/mypageblog/view/userid/470737/blogkey/2516741/
Currently he feel too stressed out and tired to write properly. He's helping out with the family business and handling a day job, and some changes at his company scheduling means his work schedule's in total flux right now (he's gained over 10 kg this past 2 months).
He hopes to get his work-life balance in order before they start writing again, and asks for the readers' understanding and patience.
In addition, he was also busy with moving, getting said new job, and proposing to his live-in girlfriend. https://twitter.com/iris_laevi/status/1356567611480317953
@WhimsiCat @saredesu Someone who's read some Chinese translations of the LN version says the LN version fleshes out quite a bit of Kousuke's motivations for wanting to become the strongest.
https://forums.animesuki.com/showpost.php?p=6459073&postcount=202