Pick up python and start automating stuff at work. Use the tools as the basis for a SaaS. Profit.
If you want normal, boring work to do why are you complaining about having nothing to do? The most normal, boring work of all.
I am complaining about having nothing to do because I want work to do, to contribute to a team, to work with other people and befriend them, but it's hard when I feel so arbitrary.
Such an odd statement. Automation (and programming in general) is probably not for you.
Perhaps look at other opportunities to help in the company? Surely they would be happy you have completed your duties...