Its not a white or black thing. It is a gradual process. India has been controlling these countries for a long long time^
Like I have been saying SA is Pro-India with contorl of RAW in every part of thier political systems
So getting Bangladesh, Nepal and even to some extent Sri Lanka into Chinese alliance network will remain a pipe dream in the foreseeable future
The difference now is that China is gaining influence in the region.
Sri Lanka has already started slipping away to China.
Bangladesh's elite have started looking to China. Only their leaders are beholden to India, and even them have started distancing away from India
Nepal had already mostly left India's orbit by the communist Party, but China's influence was not enough which is why you see it now recalibrating to closer India ties. However even this country, is still much more pro China than say 10 years ago
Overall the trend is clear. China is gaining influence and is gradually excluding India's influence from these countries. Dont worry, this is a gradual process and China is making progress on the whole SA region. Plus lets not forget that the PLA operation against India last year has won China a lot of credibility on the region that it is ready to oppose India.
So every SA country now can rest easy knowing that China is willing to oppose India
if India starts encroaching on it's smaller neighbours. India also knows this which is why India has started toning down its aggressive actions to its periphery
The moment India tries anything, a country can play the "improve relations with China" card and then India will stop on its tracks