I think these are reasonable guesses and you can kinda eyeball the differences in how each missile look.
The main point is not that YJ-18C is bad. I am sure its a good missile. My question is mainly about why PLA chose not to pursue a JASSM like missile with very large wings. What were the trade-offs of both approaches. And if its beneficial for PLA to work on a JASSM like missile. Could they get better range, perhaps 3-4 thousand KM air launched missile with a JASSM like design but as big as YJ-18 in length.
JASSM/LRASM are a smaller weapon than YJ-18C, which is why it is stubbier/shorter and comparatively makes its wings look larger.
AKF-98 (which we saw a few years ago, and which we know is in PLA service and also offered for export as CM-98) has a length/wingspan profile more similar to JASSM/LRASM, which makes sense because it is a shorter ranged and lighter weapon than YJ-18C.
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Putting it another way, asking "why PLA isn't developing a missile like that" is a bit of a loaded question, because you make it sound like the JASSM/LRASM form factor is desirable or superior to something like YJ-18C (or indeed, like AGM-181 or Kh-101 or even what LRSO is expected to look like), whereas it is instead that JASSM/LRASM is just... a shorter ranged weapon.
To elaborate, your view towards JASSM/LRASM being somehow "unique" is flawed to begin with, because there is nothing about its planform or its "wingspan to length" ratio that is unique or inherently superior.
It is merely one configuration among many for an air launched stealthy cruise missile that can be carried by tactical strike/fighter aircraft.
AKF-98 is one example of it (from China) as I mentioned before, but there are other examples such as:
Taurus KEPD (Germany)

Storm Shadow (UK/France)

(among others)
So if you want to talk about a PLA equivalent to JASSM/LRASM, what you're really asking about is a "stealthy multirole cruise missile that can be carried by tactical strike aircraft".... of which the AKF-98 is your answer.
If you're asking about "stealthy multirole cruise missiles" in general for the PLA, then both YJ-18C and AKF-98 fulfill your criteria.
If you're asking about a "stealthy multirole cruise missile with the specific wingspan/length ratio of JASSM/LRASM" then no such missile exists outside of that specific type (either in the PLA or elsewhere in the world), but then one would ask why on earth is that important to begin with??