I am all for these kinds of fun hypothetical posts but I don't know how moderators will react to it.
Anyhow, you seem to desire making the next gen single engined fighter into a fighter-bomber, like F35 is.
What's wrong with just having a fighter with secondary bomber capabilities?
The drawing above seems to suggest a whole new engine, or at least a radically upgraded ws15 core.
What's wrong with simply taking a normal ws15 that j20 will hopefully fly with circa 2025 and designing the whole plane around one of those engines? 150-180 kn of thrust is a massive figure, so it's going to be quite a potent plane. Perhaps it won't be able to lug tons of large ordenances, but that's why it's fighter first and striker second.
Overall layout may indeed remain the same if its working today on j20. Making it slightly less beefy, shorter etc would be a given, like you did it on your drawing. Weapon bays should be of quite a bit smaller volume, though. Ideally, the plane might have a single ventral bay, as long as J20, but a bit narrower. (and no side bays) A 1,2 meter wide bay designed so it doesn't need the mid bay support wall like J20 has. Or even narrower, just so the wall separator is excluded. 4 pl12 class missiles would be ideal, but even if just 3 are possible, that too would be acceptable. And then when the planes are used operationally, each pair tasked for fightercover and or intercept might have different loadouts - with one having pl12 and other one having 2 pl10 and 2 pl12.