I'm sure Russia and China would be more than happy to help on that front, even if their shit is sub-par.
Military procurement is not a "Cool i'd like to buy 12 S-400's, 100 J16's and 25 SU-35's please!"
These contracts take years to iron out and further years to fulfill.
These countries are not going to tolerate remaining defenseless for decades whilst this stuff comes to fruition. For example, Chinese production on the J-16 is at very high capacity and they're able to churn out, at best, 2 squadrons a year. Not only that, you have to retrain hundreds of crews, pilots, technicians and give up all the institutional knowledge you've gained over the past decades to start anew. Then there's the problem of working out how to use these new weapons that they're unfamiliar with, how they fit into existing doctrines etc.
It's a non-starter. Nation states will never even consider just swapping their military contractor base out overnight.
Let me give you an example, India and France signed a deal on the Dassault-Rafale back in 2012 and in 2021 the first active, viable, Indian Rafale Squadron, "IAF 101", went live. 9 years for a Squad of 18 fighter jets and its corresponding logistics, technician, and training crews.
Now, find a way to replicate this for their entire air force, army, naval forces, small arms, vehicles etc etc. This is not going to happen.