No, the very same players don't play well for India. Case in point MSD, who seemed to be unable to strike the ball whilst playing for India. However zfor CSK, he magically transforms into a beast.
GT- again, not happy with Hardik at 3. Let the IPL staff remain in their cosy confines.
Right Dhoni was absolute dud in international cricket in his final years.
Either you bowl him a left arm spinner/leg spinner or just bowl short and wide with pacers.
He was really struggling to get going but rather played some good defensive innings in low scoring games.
Neither of these are related to what I've suggested though and are arguments in bad faith. Dhoni for one played past his peak since 2016 for India, it was clear as day to anyone seeing it and had it been anyone else or in another country they would have been put out to pastures new with a proper succession plan in place. However we don't do that here for obvious reasons. If anything the Dhoni point the both of you have made only strengthens what I suggested earlier, CSK used him earlier in his decline to either come up early and shore up the innings/save NRR or come in to give him time to target a weaker bowler. Since his international retirement he has been reduced to mere cameos in the last two overs which is the best use of him. Kohli's India blatantly ignored the calls for everyone (including from the man himself) to bat him at four and solve two issues in one go because Dhoni's strike rotation was not as fluid as Kohli's at that point and Kohli wanted to only score off singles and doubles without risking boundaries in the middle overs unless required. They also refused to hide him down the order and rejig the lineup to compensate for that other than in very few games.
The Hardik example is also misplaced. Gujarat have built a squad that isn't rich on top order options and have lost one of their premier overseas options to injury and their rising star to it too before resorting to Hardik at three. Besides it has been the wish of Hardik himself to bat higher up and reinvent his role to enhance his versatility (and no doubt make his spot more secure in the Indian side by appealing to certain metrics). You wouldn't get the same result in the Indian team if you hired some of the brains behind these two IPL sides because they've got better options to select for those spots and can point out to Hardik that he is best served by playing in the middle order with a risk of losing his spot if he doesn't cooperate.
We've had stories of how IPL has helped players deal with pressure better on the international stage and how it has helped them in other areas and yet for some reason making use of similar benefits from the backroom part of it is a no go? Why?