in total thats 1097 more 4th+ gen fighters
So, 1800+1097 = 2900
China is still just 50% of that number.
Personally, I think 4.0 gen aircraft are going to be obsolete by the mid-2030s. The new baseline for modernization should be 4.5 gen (i.e. 4.0 gen with AESA + BVR armaments). By my estimate, the US has about 2100 such aircraft, if we count the 600 F-16 that are supposedly scheduled for upgrades. The PLA has about 1100, assuming 240 legacy J-11B are all upgraded. That's a gap of about 1000 in modern aircraft.
From what I understand, Lockheed is expected to produce around 150 F-35 per year. Maybe 25% of that is intended for foreign customers. So about 110 F-35 will added to the US inventory per year. That's roughly comparable to the expected J-20 production rate. The PLA will have to gain ground by producing additional modern aircraft like the J-16, J-15B, and J-35. If the PLA adds a total of 50 such aircraft every year, it will take 10 years to narrow the gap by 500.
Of course there are other factors like the number of 4.5 gen aircraft the U.S. is retiring, and the NGAD and F/A-XX that may start production by the end of the decade. And who knows how many loyal wingmen are being produced by either country.
Overall, I think it will take 10 to 15 years for the PLA to catch up with the U.S. in the number of modern aircraft. But as I alluded to before, the U.S. military will be limited by the logistics of deploying those aircraft to the Pacific theater.