The Indians are not interested in a research article. They want a finished product. Only recently were the avionics finished for example.
The Russians are right now manufacturing the first serial production Su-57. Still it is not the desired configuration by the Russian Air Force.
Which means production will be at a trickle and initial manufactured units will be likely used to train pilots and establish doctrine.
Only once the Article 30 engines become available, IIRC with the 12th production Su-57, will they consider increasing the orders.
There is no rush to put it into production before it.
Russian officials have stated this several times. Fact is, as is, the Su-57 even with the 117S engines can outperform any 4th generation fighter.
It also has way better aerobatic performance than the F-35. But with the new engines it will truly become a 5th generation fighter.
The US won't have any competitive product against it. The F-22 is not in production and was never made available for export.
The F-35 is pathetic in terms of kinematic performance. Sure it has better avionics right now. But I doubt the Russians will keep the avionics at the current level forever.
As is the avionics and weapon systems of the Su-57 are already better than what the F-22 had at its inception or indeed has right now.
The F-35A is extremely agile, if you aren't able to see that in that 9G RIAT breakout turn, I can't help you, to be honest there's NEVER going to be an SU-57 inside the "kill" envelope of the F-35, the F-35 will see the SU-57 at well over 100 nautical miles, maneuver for an optimal kill shot, and do the dirty deed...
The F-22 on the other hand is so far ahead of the Su-57 on almost every level, so the Su-57 will be like a "lightning bug" on a starry night, easy to see, and easy to shoot.....
The F-35 is pathetic?? come on, you really ought to at least watch the RIAT video, and now we are going to have a whole summer of fun, with the F-35A!