Futaba channel maybe. Nowhere else as far as I know just uses base futaba. The jap sites look like they haven't adapted at all to the times. It looks fucking ancient even by imageboard standards. And slow is the old experience. Imageboards and textboards were mainly always a niche thing. Only 4chan, Futaba channel and 2ch the textboard were ever fast or notable. For the most part they've always been a few guys splitting off some niche. Like 7chan being elitist, 420chan for stoners, 711chan for raiders, 99chan for just oddballs, and so on. But these were always fairly slower. But you learn to like it. When you get too much activity it really diminishes the quality. So you need to find a sweet spot somewhere.