CS Lewis, Paul's letters in the NT, and Aquinas, in order of difficulty. If you have kids, LotR can be used allegorically (sorry JRR!) to explore some ideas, though Lewis' fiction is basically purpose-built for that, and are generally easier reads (so you can use them with younger kids).

When you come to understand the 'problem of evil' is a massive, secular cope, you're on your way.

Doug Wilson is a pastor online who tackles modern issues and he is pretty accessible. He'd be more for an adult looking to dig deeper, though he also has home school material i haven't looked at yet.

CS Lewis, Paul's letters in the NT, and Aquinas, in order of difficulty. If you have kids, LotR can be used allegorically (sorry JRR!) to explore some ideas, though Lewis' fiction is basically purpose-built for that, and are generally easier reads (so you can use them with younger kids).

When you come to understand the 'problem of evil' is a massive, secular cope, you're on your way.