An anonymous Tumblr user asked, “How plentiful is magic in S&S?”
Magic is actually very common! Half of the species of the galaxy, give or take, have cultures built up on magic rather than classical technology. Magitech, magical solutions, and intricate spellwork all play a role in the modern lives of those in S&S.
You should expect to find magic items just like in normal 5e as well as enchanted guns and other unique things. As for the playable classes, many of them utilize magic as their primary mode of operation.
In Chapter One of the Core Sourcebook, you’ll find a whole section that talks about the science and mystery of Dark Matter Magic and how it interacts with the various planes that interconnect with the galaxy.