if the war is imminent it doesn't take quad to immediately declare a military alliance solely against china.
Even if US wants to help, what weapon training/ tactics/ compatibility do Indians have with US/NATO weapons? If Ukraine war showed anything, advanced knowledge and training on weapon systems is more important than the weapon itself. Can Ukrainians use F-16 if sent overnight? No! They don't even know how to use HIMARS. Fighter jet training takes years.
The greatest asset against Chinese is your air force. But with weapons of Soviet era with some French and Israeli systems here and there, Indian Air Force looks like a pasta salad.
Over-reliance only on Russians and French is a strategic mistake of India. They cannot provide what India may need at the time of war in meaningful quantities. France barely makes 40 fighters, 5 ships and 15 artillery pieces a year. They don't even have strategic ammunition reserves. For comparison, US produces over 200 top class fighter jets a year but none will be useful to India if time comes without training.
Since only US/NATO have the industrial capacity to provide immediate and immense help against China, diversification of your sources is the smartest and most important military need for India.
You must be able to absorb US (NATO) technology and train on systems far in advance in order to benefit. You have a big defense budget- so go lease few F-15,16,18. Learn how to use US EW, SIGNIT, ELINT, fire few AMRAAMs and Sidewinders (US produces 5 times more A2A missiles than Europeans). You will run out of missiles and ammunition needing diverse sources to fill the need in time.
You are really fortunate to have all this tech access and if a real war starts with Chinese, you will be grateful to have prepared to use it.