Coincidence. I had no idea about Lightbringer before the campaign started. The DM decided to run that adventure as an intro before starting the group, so he didn't know there would be a Light Domain cleric. It is a Forgotten Realms world, but my character is from Mulhorand worshiping Ra not Lathander. Still, there were good roleplay opportunities involved in later adventures with respect to Ra and Lathander worship. In character I view it as Divine Providence. We've been playing the adventures from Yawning Portal and a number of them involve a Sun deity or Lathander worshipers. I haven't read the book. Out of character I didn't get the impression the DM designed things to incorporate the Sun theme or Lathander on purpose because of my character but rather the modules themselves are written that way. If he did major kudos to him.
The DM allows Lightbringer to act as a Divine Focus, so I don't need War Caster. Such a nice DM.
For the peanut gallery, yes, I am capable of liking the DMs I play with.