The main difference is that the abridged fanfiction of Dragon Ball Z is likely to have a different take on the story. So when Akatsuki watches it, they're seeing a more modified version. Dragon Ball Z is the original, while the abridged fanfiction may cut out some parts, add new jokes or even change character personalities a bit.
There are no such inappropriate 'Straight Shota' stories in the official Dragon Ball Z canon. Dragon Ball Z mainly focuses on epic battles, power-ups, and the adventures of Goku and his friends to protect the Earth from various villains.
Saiyans may watch Dragon Ball Z fanfiction because it offers a fresh perspective on their culture and history. The original series only scratches the surface in some areas. Fanfiction can fill in the gaps, showing things like how Saiyans celebrated their victories or mourned their losses in the past. It can also show different relationships between Saiyans and other races in more depth. Moreover, some fanfictions might introduce new Saiyan characters, which can be exciting for those who are interested in their own race and want to see new interpretations of Saiyan traits and behaviors.
One alternative is to focus on character backstories. You could write about the early days of Piccolo, how he came to be the way he is. Another option is to do crossovers with other non - sexual universes. Maybe a story where the Dragon Ball Z characters meet characters from a magical anime world and they have to work together to solve a problem. Also, you can write about the relationships between the characters in a platonic way, like the deepening of the friendship between Gohan and Krillin.
A Kryptonian in the Dragon Ball Z universe could potentially be a very powerful addition. Their natural abilities like super strength, flight, and heat vision could make them a force to be reckoned with. However, they would also face challenges as the Dragon Ball Z world has its own power scale with ki-based powers. They might have to adapt to the different fighting styles and power sources. Maybe they could learn to use ki in addition to their Kryptonian powers, or they could find a way to combine the two in unique ways.
Dragon Ball Z is both anime and manga. The anime was adapted from the manga and they share the same story and characters, but presented in different mediums.