Forget the JED-RUH leg on EK, book everything else by feeding leg for leg into ITA matrix to get s price and see if you get the fare you need. Consider just a long stopover in DXB returning from BEY and separate tickets to JED and back from RUH..
Also consider flying only Bey-dxb and then ruh-dxb, with dxb-jed on a separate ticket.
I regularly book these kinds of itineraries but with BOM and HYD instead of RUH and JED. I'm flying later this week:
Cpt-dxb
Bom-dxb-muc
Ams-dxb-cpt
Separate ticket dxb-hyd
Look at the fare rules. Stopover, stopover duration or advance purchase might be causing it not to meet J Saver Rules. Also are you checking availability on an O/D basis (MAN-BEY as a single search rather than MAN-DXB and dxb-bey separately. Married segments make these kind of itineraries hard to accurately predict and price since you can't sear h married segments with stopovers on EF (but Matrix will marry them)