There is so much red tape with western equipment and u never really own it, because if u want to sell it off as it gets old u still need to seek permission.
You also have to remember the cost, maintenance, and fit for purpose aspects. As well what u already have. If you have been operating Soviet systems turning to buy modern Russian equipment would be easier to integrate, maintain, as well as training, and modern Russian equipment can accommodate Soviet systems. But changing to western equipment is a whole new learning curve, increased risk of accidents as well. Same goes for Chinese equipment.
The costs of western equipment is far more expensive than Russian and Chinese equipment. And going back to fit for purpose will have a major deciding factor. I remember the tender for Thai armed forces requirement for transport helicopters. They chose mi-8 over the black hawk, because it was cheaper and bigger, and easier and cheaper to maintain.
And we all know about the west using expensive javelin missiles against mud huts in Afghanistan, pure overkill, while Soviet and Russian systems would have been cheaper option such as SPG-9, sagger, fagot, konkurs, etc. It's why the Afghani army were still using and being trained on SPG-9 the training was being provided by Ex Soviet countries, Poland and Mongolian troops.
The thing I like about Russia's offerings on arms is that they have something for every type of threat and for every budget. Whether it's new modern Russian systems or upgraded Soviet systems they tick all the boxes. The west don't have such offerings. It's expensive new equipment or expensive second hand equipment that both come with red tape.