bullshit... Russia gave them TOT thats why u see so many variants of T-10(Su-27,Su-30,Su-33) all are made under collaboration with ruski natasha bitch,,,
and Su-35 was given with some TOT for Jet engines. S-400 they have got is nothing different they will get license and starting making copies of that also soon.
Chill bro yes they did that they allowed them license manufacturing up to the extent that even Chinese started building them using raw materials and spare parts etc all were manufactured by them. We can also build Su from raw materials but they have entangled us in contract to get spare parts and raw materials from russia only. That's why India didn't went for mig 35 either. There is nothing new they have to offer in terms of TOT and we don't want to pay them forever for nothing.
Coming back to Chinks, they went one step ahead and renamed the Su and cut the Russian license fee/loyalty and build it under name like J-11/15/16
They reverse engineered the engine with help from old Soviet scientists who were unemployed after the split.
They got license from Ukraine /Israel to build missiles etc and then improved over it by changing the name and paint.
So Russia isn't exactly happy with it, it's just that they really need their money to keep their defence firms running specially after the ban imposed by USA.
And S-400 is certainly downgraded because russia know they will definitely try to reverse engineer it.