After having luck with changing the outbound of CAI>DOH>BOS to KRT>DOH>BOS I really tried to change BOS>DOH>CAI to end in JIB (Djibouti), but no amount of logic would prevail.
I hinted that a shorter flight to JIB was better than them flying me to ATH or IST then putting me on a partner...
I had ZERO luck and eventually just said fly me to KWI. They said the flight from KWI to CAI would be in Y so I decided to just stop there.