In my last blog post on Sin, I talked about the danger of single stories. My understanding of the cross has been formed in a similar way, and it's been the discovery of different stories about the cross that have opened me up to the richness and depth of what it meant for Jesus to die on the cross. I don't want to talk about it too much here, but suggest a few resources where you can hear a mix of stories which might expand things for you.
Firstly an interview with Brian Zahnd where he talks specifically about the cross and some of the issues with his original understanding of the cross, penal substitutionary atonement theory. If you prefer books and would like a more in-depth look at it, he's also written a book called Sinners in the Hands of a Loving God.
In the UK, Steve Chalk caused a bit of controversy a few years back when said he no longer believed in penal substitution. He currently has a series on youtube looking at 95 different questions to do with theology and our understanding of Christianity and the bible. A few of them related to the cross are... question 34 - Misunderstanding the Cross has made Church ‘angry’ and ‘judgemental’. Question 37: Making the cross about vengeance stops us from loving our enemies and Question 59: Is our salvation dependent on the cross?
I couldn't not mention some Nomad podcasts, so a couple you might find interesting are an interview with James Alison on scapegoating, how civilisation harms and how the cross heals. This is a pretty dense interview but very interesting. This interview with Brad Jersak on the orthodox way was brilliant. It's more about the Eastern Orthodox Church but the theme of the cross comes up a lot.
That should keep you going for a bit :)
I find reading, listening and thinking about these different topics is a helpful first step, but it's through chatting about them with other people where I'm able to land theory with practice - so do seek out friends to chat through your thoughts on this massive topic.