Ever17 missing from your list was the first thing to immediately come to mind since you were bummed you couldn't fiind anything "big and epic." I think that may fit the bill for you.
There's Cartagra and Kara no Shoujo, both are detective stories. The protagonists and setting aren't the typical ones you'll find in a visual novel, plus looking at your list it might offer you something different than what you've read.
d2b vs Deardrops since you've read both KiraKIra and Deardrops.
I'll finally recommend Zanmataisei Demonbane, it's a blend of a lovecraft setting and mechs.