Tom Holt/K.J. Parker’s fantasy works do include some Byzantine names and allusions, but they tend to be rather mild. I think the Fencer trilogy (Colors in the Steel, Belly of the Bow, The Proof House) probably go the deepest into Byzantine allusions, with the first book being set in a massive Constantinople-like medieval city that is sacked by the end of the book. If you want to go the science-fiction route, Arkady Martine’s Teixcalaan books (currently just A Memory Called Empire and A Desolation Called Peace) rework the Byzantine Empire’s annexation of Armenia in the 11th century into a space opera setting.
Do you know of any (even halfway decent) fantasy set in a Byzantine setting? A Shadow and Bone set in Constantinople for example.
Sailing to Sarantium and its sequel Lord of Emperors, by Guy Gavriel Kay.