I have not read the original manga series, but I did enjoy the 11-episode INUYASHIKI LAST HERO anime from 2017. This live-action INUYASHIKI movie features a great cast, including Noritake Kinashi and Takeru Satoh in the lead roles. The acting is good too. The ending is a departure from the way the anime went. I don’t know which version is more faithful to the original.
I’m not fully convinced that there’s an anti-ageist agenda going on, but the movie is certainly an effective illustration of how wonderful or frightening great power can be, depending on who wields it.