How does Saturn function in a chart like this? Is the influence more or less beneficial l, considering it is a coruler? My natal Saturn is in cancer and the fifth house. What can I expect?
The fact that Saturn, among Uranus, is your Chart Ruler doesn't mean that it's more or less beneficial to you. It means that its placements, Sign and House, as well its aspects with other Planets are dominant. It represents you better than any other Planet.
In your case, Saturn in Cancer and in the Fifth House can be problematic with your family (parents but also your children) and your home.
On the other hand it makes you proficient in controlling your emotions, when meditation is applied it is a great help in Life.