I was enamored with .38super back in the early 90's when IPSC shooters started using it for competition to reach Major power factor but with less recoil than .45acp. And I remained so for quite a long time. Especially once ramped barrels came about, more fully supporting the cartridge base and allowing for more safely achieving performance nearing .357magnum.
But then .357SIG happened, as well as 9x25Dillon. Suddenly, .38super wasn't as super after all. But I still liked the capability it represented. For a brief period, I had a Caspian wide-body .38super racegun with compensator that I bought for a song and was going to convert into a non-optic carry piece. But that's a long story why I abandoned that.
The shorthand is that to get out of .38super what it can potentially offer requires handloading. Buuuut,...the cartridge is a little funky, in that the bullet diameter is unique to itself, and the semi-rimmed case is not optimal either.
Back in the early 90s, Winchester tried to invent the replacement for .38super with the introduction of the 9x23Winchester. It essentially duplicated .38super ballistic potential, but used a standard 9mm .355 diameter projectile and a rimless case. Essentially, the 9x23 is nothing more than the pre-existing 9mmLargo, but loaded to more modern pressures. You can fire a 9mmLargo in a 9x23, but don't try the reverse, or you'll blow up your 9mmLargo pistol. The problem though, was that so many competitors were already so heavily invested in .38super dies, and bullet molds and gear, that they were resistant to just switching over to the 9x23. And a little less than a year after the 9x23 was introduced, the .357SIG hit the scene. Because the .357SIG (based on the .40S&W case) could be adapted to and fit and fire in guns originally designed for .40 and 9mmPara, whereas the 9x23 required guns with frames capable of longer cartridges,...the .357SIG just was more readily embraced. Almost no one remembers the 9x23 now.
If I were to craft a hi-cap pistol today in the image of the .38super, I would chamber it in 9x23. The projectile selection and availability is better. Longevity of the cases to be reloaded is better. Load data between the two is nearly identical. Even new production brass is not a challenge, thanks to Starline, who manufactures it still. (They also do production runs stamped either 9mmLargo or 9x23, and both will work.) Regular 9mmPara dies can be used, even.