To improve a relationship takes two sides and there has to be a common understanding. Where is the common understanding? This is the guy who defines China as India's number one enemy. Did he do anything positive between the two countries?
Yes China don't want to have a hostile relationship with India, but If that's what India wants, so be it. You can't get there by being a "nice guy". China allowed India to join Shanghai Organization, made India the second largest shareholder of the infrastructure bank. Provide loans, expertise and technology to build India's infrastructure (telecom, energy, transportation), essentially help them develop risk free. What did China got in return? Doklam and Galwan.
If I'm a hardliner, I would say send Indian condolences. It's a swipe at India's military. I'm sure Modi supporters would see it that way and fanfare another round of hatred.
Now, the best China can do is to ignore it like nothing happened. There is nothing bilateral.