I just watched Maangchi make Jjamppong, she made the broth with dried anchovies and seaweed. She threw the shrimp shells away and could've used that too.
That broth is easy to get ingredients for and easy enough to make. I think most of the flavor is coming from the fresh seafood being cooked in the broth than the light starter broth she made. I noticed adding a pack of the Paella mix with claims and squid really made a difference in flavor, I think it's the clams that give it that extra seafood kick but it's not overpowering.
That recipe will work with curry added too. I do basically the same thing and add a tsp of Garam Marsala and yellow curry when she adds the pepper flakes.
I used that crab paste with bean oil last night in a catfish and shrimp coubion dish. I didn't have shrimp broth so I added a tsp of it with water and it gave it a good light crab flavor. I still need to play around with those products and see if I can make a good quick seafood broth from jarred products. I'll also pick up some dried anchovies to try that too.