I want to point out that
@kwaigonegin is wrong about the J-20's intended role; it's a F-22 analogue intended to provide an 80% counter at substantially lower costs. In fact, the J-20 is superior to older blocks of the F-22 given the latter's lack of IRST.
The PLAAF is not the Soviet Air Force; China's strategic situation (some land borders, but mostly maritime borders) mean that airpower is crucial for the PLA's functioning in a way completely unlike the Soviets, as the PLAN cannot function with merely an air denial (anti-ship missiles are more capable than that of the USN, but anti-air missiles are less so) air force.
Likewise, given the limitations of naval power, China's paltry amphibious landing capability, and not to mention counterforce anti-ship missiles, the PLAAF is likely to be the main striking arm of the PLA in its region, with the PLAN operating more as area denial and as a meatshield.
***
Considering the cost difference between lobbing bombs and lobbing missiles in a sustained fashion (bombs are far cheaper because their delivery vehicles are reusable), the PLAAF requires strike capabilities, but the J-20 is ill-suited for the task, given that it's considerably difficult and costly to extend stealth aircraft. An interceptor variant with a larger bay is possible (and rumored), but extending it to full strike will require considerable changes and time, time the PLAAF doesn't have with NGAD coming online within the decade.
Better to work with the JH-XX and the 6 generation fighter.