As an update to anyone interested: now we're 1.5 weeks further and I still haven't received my luggage and I am due to fly back in few days' time.
Airline staff and L&F in CGK could not do much apart from referring to worldtracer status "still searching for your luggage", which is understandable as their job scope starts only when Saudia brings my baggage into CGK.
Contacting Saudia has been a pain, their Saudi Whatsapp number is inactive, Indonesian Whatsapp is not responsive, their chat function on website is just a useless bot. So, I have no idea what they're doing in Jeddah. Either way, the fact remains that the luggage and I are not reunited.
Also I learned testimonials from some of my friends that experienced the same, where it could take weeks in one case and months in another case before they got their luggage back when Saudia misplaced theirs (if only I had known this before booking).

My own conclusion: I decide to take my future business elsewhere.
It's a shame that I liked Saudia's J class for their great service, good schedule fit, and rather affordable fares.
But airlines must also be evaluated by how they handle issues when they arise; this is where Saudia utterly fails.