Welcome to the forum @Hariboexpert
I regularly get a bag or two of coffee grounds from someone I know who works a Costa They mainly go on my lawn once dried and get mixed in the flower beds, with no ill effects. I do find they do deter slugs but, not all varietes however, I’m far from a gardener and hate it if I’m honest.
The plus points, you always get a whiff of coffee especially when it rains lol