Dhuba would be a somewhat "expeditionary" trip.
Since you're looking for shore dives, there are a few dive shops in Yanbu (five to six hours south of Dhuba) to source tanks but I think dive shops will totally thin out north of there until you get back into striking distance of Aqaba. I've never used the Yanbu businesses or their tanks but local expat friends have without incident. That's the limit of my insight there.
Prior to COVID-19, key staff from the US Consulate and I (with all the resources of a large Western Consulate) intended to do some "expeditionary" diving out of the northern coastal towns but gave up because it was just too hard to pull things together and was going to require more time than we could afford.
The construction of NEOM hasn't yet created a bow wave of business opportunists to take advantage of interest in northern diving. And COVID-19 has really put a damper on Vision 2030 initiatives as Crown Prince MBS has had to pull back resourcing to some of Vision 2030's more aspirational initiatives like the tourism industry.
Nothing above says you couldn't rent a vehicle in Yanbu, load it up with a pile of tanks and just go poking around the northern coast. Totally doable but it will be austere, you'll need to be self-reliant and it will require some time. A rudimentary command of Arabic would make life a lot easier.
An approach from the Aqaba might be a lot easier and much more fruitful.
For vessel-supported diving, the closest reliable charter familiar with diving would be in Yanbu, approximately five to six hours drive to the south of Dhuba. Yanbu has reliable commercial air service from Jeddah, Riyadh and probably a small handful of local foreign airports (EGY, JOR, etc).
I'd probably start with Dream Divers for your research (
Dream Diver). I don't know if they have a small vessel up in Yanbu. When they run their 26 berth LOBs out of Yanbu, they steam up from Jeddah. I've dived with Dream Divers quite a bit and Will (the DM/guide) is a good guy. Although Dream Divers has done some scouting dives north of Yanbu, I don't know how much he knows of the Dhuba area.
To charter a smaller boat operator local to Dhuba would require you to be fluent in Arabic with time on the ground or to have a trusted agent fluent in Arabic who can dedicate time to secure the support you desire. Business in KSA is much different. Business owners and customer service employees don't seek out opportunities to do business with you even when you make it clear you are ready to pay for a service. What is promised over e-mail or the phone and even face-to-face will not necessarily be what you get. For many businesses, just the notion of an idea is regarded as sufficient rather than providing a service that meets reasonable expectations or, most familiar to Westerners, is beyond reproach. You may be able to secure a vessel to take you out but if anything were to go even slightly awry, expect it to quickly turn into a worst case scenario.
Good luck.