Construction of India Myanmar Thailand Trilateral Highway has started already
And it’s not just trade ASEAN needs india to counter China as well ASEAN is a group of small countries they cannot counter increasingly assertive China on their own no matter how rich they get
In what way does ASEAN need India to counter China?
By being master of India and getting India to militarily engage China? If so, how on earth would India militarily engage China? That's like asking a 1980s China to conventionally engage the US in Hawaii. Geography is not friendly to India wrt ASEAN or against China.
ASEAN's military worries with China can be placated very easily if China wants to find a way to set their minds at ease. It has no disputes with most of ASEAN - wrt Philippines and Malaysia, both are increasing trade with China for the last few decades despite dispute tensions being there.
Holding an exercise with India means f all. Like honestly, ASEAN navies held a maritime exercise with India... end of China wooo! Jai Hind! ... No. Nothing changed. No military engagement, increased trade, more agreements signed with China, more friendliness with China actually with Malaysia and Philippines. Sure all things go back and forth and change but militarily, ASEAN just wants China to not invade them basically and despite disputes, China hasn't and hasn't got plans to.
If China reaches its full potential and economic/industrial size in decades time, military engagement against China would just be out of the question and the entire dynamic between China and ASEAN would have even less of a military tone (as small it its current one already is). China is no Russia. China is no USA. If it resorts to active aggressive and unfair postures it wouldn't be military like those former nations.