So this seems to have just ended in the official raws, and lemme tell you, super unsatisfying ending from what it looks like. Spoilers:
The gist of it is they just kinda accept that the world has giant bugs and crustaceans now, and people will "find a way to adapt, but oh hey look at all this neat stuff we might be able to make now with the new materials." People were lost along the way, thems the breaks in the name of progress. We never revisit the second island, those people are just in limbo because it's happening everywhere.
I mean take that with a grain of salt and if it helps you decide to keep reading the next 50 or so chapters as they translate out, or go ahead and drop reading, then cool.