Looks like Koshien is tomorrow already. The "day before" stream is underperforming HARD in relation to 2022 and 2023. Here is for the other years
>peak :: date :: title :: nameEn :: video_id
>65125 :: 2021-08-12 :: にじさんじ甲子園2021 大会直前!前日特番【 #にじさんじ甲子園 】 :: Nijisanji :: rX6ODupqCwM
>101488 :: 2022-08-11 :: にじさんじ甲子園2022 大会直前!前日特番【 #にじさんじ甲子園 】 :: Nijisanji :: zE9WP1N12yM
>94194 :: 2023-08-10 :: にじさんじ甲子園2023 大会直前!前日特番【 #にじ甲2023 】 :: Nijisanji :: RGf2CS7c0aE
>64968 :: 2024-08-09 :: にじさんじ甲子園2024 大会直前!前日特番【 #にじ甲2024 】 :: Nijisanji :: qyf1J0oT1yk

It's doing better than last year's one but last year was in itself another massive underperformance.