I've been looking for a story for a couple of weeks, but what I can recall is so vague. I only remember a subplot where Thor has become King of the Asgardians (maybe on Earth?) and is working on diplomacy with other realms, I think. Because of Odin's death, the other realms aren't thrilled to honor the same biased agreements and want to make Thor work for it.
Odin's brother(?) is an advisor, knows the truth of Loki's heritage, is part Jotun himself (maybe? he's definitely familiar with the situation), and suggests Loki travel to different realms as an envoy, specifically to Jotunheim so Loki can learn about his heritage and meet the rest of his family. I believe they go to another realm (Alfheim?) first, but eventually Loki reluctantly goes to Jotunheim. Loki meets a couple of half brothers(?) who are not welcoming to begin with but eventually are pleased to meet more family.
It's just this subplot that's stuck in my head. I don't actually remember the plot of the main story. I believe it is actually more about Tony Stark preparing for Thanos, but it's been a while since I've read it. I'm not even sure if there is a main relationship or if it's gen.
I hope this sounds familiar to someone because it's driving me crazy! Any help will be greatly appreciated.