I haven’t designed a bike seat, but I’ve tried a bunch, and tried to discern which claims held water.
My conclusion is that individual anatomy, general bike fit, and saddle time are the primary issues in whether your … parts… will hurt after riding. Width of the saddle needs to correspond to ischial tuberosities. Knowing how to sit on the bike, making sure cockpit length and all other angles correspond to your riding position and style, will influence the pain or lack thereof in the behind. And frankly the hurt goes away or at least lessens in importance as a rider puts more hours in.
Its not a seat, or a chair - its a saddle. If performance is the goal, there are few ways around a relatively firm, narrow saddle that will still allow for proper pedaling and body English. If comfort is the goal, then it will come down to individual preference.
Not saying there aren’t millions to be made designing something else, but improvements in comfort and performance are probably easier to come by with addressing the topics above.