Soft science fiction of either type is often more concerned with speculative societies and relationships between characters, rather than speculative science or engineering. The term first appeared in the late 1970s and is attributed to Australian literary scholar Peter Nicholls.
Soft science fiction, Wikipedia
Science Fiction is a scale
Sci-Fi exists on a scale from hard to soft; ranging from “science to explore the science” to “made-up science to explore the story”.
The point of interest for me is the fantastical that gives rise to the story. I enjoy some hard Sci-Fi but I generally prefer mine on the softer side. I want a good story first and foremost.
Here’s a better explination
There are many sci-fi purists who don’t consider works categorized under soft sci-fi to be “real” science fiction, because it’s more concerned with the fiction rather than the science. However, since some of the most well-known sci-fi works are technically soft sci-fi, this seems like a bit of a reach. Soft sci-fi stories are just as valuable as hard sci-fi ones, and can actually be a good gateway for new sci-fi fans, as hard sci-fi can often be difficult to comprehend if one is unfamiliar with the genre.
Hard Sci-Fi Vs. Soft Sci-Fi, Explained; GameRant