If you're helping pay for the internet then lay down some rules. If she wants to make all the rules about who can access what then she can pay for it all herself, and since it's in her name she's the only one that's legally responsible for it.
Oh no. Kid safe mode. No one in the history of the internet has ever figured out a way to bypass filters! Look, it’s real simple- if you’re splitting the bill and don’t like it, tell her. It’s legitimate that filters could block you from actual sites you need for school, for instance anatomy or any orther “non kid safe” content an adult student might need to access. I once worked at a company who did manufacturing, and the work filter blocked me from certain vendor sites that only hosted .pdfs with technical documents on industrial machinery. If she’s paying it all, you can still bring this up, but it’s her money her rules unless you get your own service. There’s always bypassing the filter too. But ultimately, part of being roommates is learning to communicate and live with others. That includes people you may not agree with, and people who may be difficult or unwilling to compromise.
Print out some poster of Jesus fanart (yk what type I'm talking about) and display it on the living room wall