The problem is, that these numbers 003, 004, 005 and so on are not used in a strict pattern. Some classify them as Type of the vessel numbers, whereas others rate them as carrier numbers. I must admit I was indeed surprised the Shandong is rated 002 since IMO the changes are not that dramatic to justify an own new class, but anyway. As such it will be interesting to see, if the next carrier will be yet another Type 003 class vessel or even a Type 004 class?
I expect at least one more Type 003 vessel.
Another possibility worth considering is that much like the 001 and even the 002, the 003 is the first of its Type/Class which is not strictly a proven or mature platform as far as the PLAN is concerned, but more like a testbed for carrier operations as well as carrier construction (first STOBAR, now CATOBAR).
So it's just as likely that the next CV could very well be a Type 004 that further improves upon lessons learnt/to be learnt from 003, much like 002 via-a-vis 001 before it.
Also, considering China's propensity to play the long game and the PLAN's habit of building ships in pairs, if it turns out the PLAN is confident about 003's design and performance, I could realistically see them building a pair of conventional "Improved 003s"/004s before moving on to a nuclear "Type 005".
This would allow China to scale up her carrier force more quickly... which is fast becoming a priority in the current geopolitical climate. There's also the added benefit of longer lead time for the PLAN to further develop their nuclear power plants and propulsion tech for an eventual CVN.
By that same rationale, when the PLAN finally gets around to building a CVN, they could well follow a similar pattern of building a nuclear Type 005 as a testbed and then a pair of proven/"proper" Type 006 CVNs, by which point the PLAN would have a strength of 8 CVs/CVNs in various modes of operation.
As an added aside, there's a certain merit to a 3-ship per class approach for carriers, as one would be in repairs, one in extended maintenance, and one in operation. So this ensures there would always be at least one carrier specific to its role available at all times. So while a potentially 8-ship (or whatever the number may be) carrier force may seem excessive depending on where you stand, it is in reality anything but.