I've only had a single world and single character since I started playing shortly after release. I don't remember how many hours I had clocked in, probably 100-150 or something on my own world (600 days), and I felt kinda same as you about dealing with Yagluth. But I still got a ton of stuff to make after him, like completely upgrade some black metal items, and I have not yet upgraded fenris armor either since the frost caves cannot be found close to center of the world.

And then there's a whole lot of building projects I've undertaken inside my "small" lodge, like reinforce and replace the roofing with tar shingles, construct actual portal tower and treasury, fortify inner and outer defenses with iron cages... It's not necessary of course, but I like being prepared for whatever nasty monsters Mistlands will unleash at us.