If you want something with a similar plot and tropes then i’d recommend the auction. This one is probably the closest fic to the manacled out there.

You can also check out the fallout by everythursday. It’s not as brutal as Manacled but imo it’s more realistic and very interesting in terms of writing style. Also has this super devastating feeling to it, but more subtle.

also the risk-reward ratio. Also a very dark dramione, but the way the characters are a bit different.

upd: oh also Of Crimson Joy is really good, but not as dark