If you buy Jf-17, all your problem will be the engine. And China is working on a new engine for Thunder if I am not mistaken. But if you buy Su series all aircraft, all of it will be your problem. You know Russia is supporting Armenia and they even gifted armenia 4 jets for very cheap price. Just think, why did Russia ''gifted jets'' to armenia? Because they are trying to have a balance between you and armenia. Even if you think, they gifted to armenia in the same time they want to sell it to you. So technically you will pay for armenian jets...
I know, Su-34 and Su-35 is great jets. Really, I must say they are much better than JF-17. (JF-17 is a light jet) but dont jump to trap of Russians. If you have 24+24, 48 Jf-17 no one from the region would dare to attack you, anyway.
https://jam-news.net/armenia-buys-four-of-russias-newest-fighter-jets/ Lets not forget that...