Is it really that much of a blood feud when the Romans were willing to restore Kadir to the throne or when they took a deal with the Caliphate instead of just massacring the last of the Turks? If that's the case, then I don't really see it being a thing.That’s nearly a millenia of blood feud the Romans had with Islam.If they have the opportunity to reconquer their lost lands I don’t think a lot of Romans would skip the opportunity to sack the Muslim holy cities,
Rhomania sacking Mecca and Medina could theoretically happen, but this one incident triggering that kind of event doesn't make sense in my eyes. There's been so many times where Constantinople has been invaded or even sacked that in a few centuries time (when Rhomania could have Egypt and Arabia), Osman's suicidal charge might be a distant memory (Again, compared to the Sack, which literally shattered the Roman Empire, this is nothing). There has to be a far more recent and egregious offense for them to act this way, and this is not it.