India doesn't choose any sides actually. It only latches onto the side that it thinks it can benefit from more. In WW2, some of them stuck to their British colonial masters, while some sided with the Axis powers. When the Axis power started to lose, most of the Axis Indians ran back to their British colonial masters. In the Cold War, India sided with the West at first, and then switched to the Soviet Union later, when the West sided with Pakistan. India is enemies with nations it has a borders with, or who are in its way, because it has expansionist dreams. India courts nations it has no issues with in hopes that it can play them against its current enemies and reap the benefits. But if these "friends" suddenly has a border with India, or are in its way, then they'll be the next enemies. India has no true friends, only friends for benefits. If India had shared a border with Russia today, we can bet that it'll end up like Ukraine.
India's war track record is actually very unimpressive. The wars that India had won were against Pakistan, a token Portuguese force, terrorists, insurgents, and unarmed civilians. When India fought against a proper military force like the PLA, they were soundly defeated. India have never experienced war like how the Chinese did. So India is that ignorant local bully who could only bully his little neighbours, but have never faced a proper opponent. When Nehru commanded his troops to invade into Chinese territories in 1962, he was high on those victories against Pakistan and a token Portuguese force. He thought that the PLA was a impoverished communist peasant army that would run away before his victorious Indian Army. Well, that impoverished communist peasant army had fought the combined US-UN force in Korea to a standstill less than a decade ago. Hence, Nehru's Indian Army got a spanking so bad, that it scarred the psyche of the Indian elites till today. Galwan 2020 was also similar in a way. Modi's India was high on that Chinese restraint in Doklam 2017, taking that as a Chinese "defeat". And by 2020, it so happened that China was suffering from a massive Covid crisis. So India thought it was a great time to stab China in the back to salami-slice a piece of Aksai Chin away. When the PLA came to stop them, the Indian Jawans thought that they were pushovers, and proceeded to assault and murder a couple of them. When the PLA struck back in force, these Jawans were sent running, freezing, downing, dying, and surrendering en masse. A humiliating reminder of the 1962 war. After that, India, the sore loser that it is, went full throttle into anti-China mode.
If India goes to war with China again. This time China must make India pay a heavier price than 1962. The Seven Sisters of the North East, Bhutan, Sikkim, and Kashmir had never originally belonged to that British-made artificial nation called "India". So, China should feel no guilt at all in liberating them from India's occupation.