Very impressed with @MottledZeitgeist and @C.Kendall’s recommendations! Super thorough, knowledgeable and detailed.
I do agree, there’s several ways to work with Surtr. The best start I can recommend, is that Surtr is the Jotunn of fire. What does fire do? It can forge, destroy, purify, etc. So when you think of what you want to work with Surtr on, I recommend you think of what the different things fire can be worked with to do.