@Avicenna
I once opened a thread, about how Bangladesh could use that 500 million USD credit for military hardware from India to buy JF 17 thunder, it was obviously a partial trolling thread on my end, but it was taken down nearly straight away, which was unfortunate because I wanted to see the reaction from all 3 sides.. but on a serious note, that credit India is giving you to use is most likely to try to entice you guys further into the Indian defence industry, their end goal is try to force you to buy 'only Indian' weapons and/ or be dependent on them for spare parts, which is not only a national security threat, but the fuss they made when Bangladesh bought 2 second-hand submarines from China was really cringy... I believe they (media) even went as far as saying Bangladesh doesn't need a navy, when they have India to 'protect' them..
As your economy grows you guys should look into joint ventures similar to the China - Pak JF17 programme, by building your own defence industries you'll become more self reliant, not having to worry about arms embargoes in time of war like Pakistan has with its clashes with shitland, you will also save on precious exchange currency.
Although I believe your biggest threat is not India or Myanmar, but the rising sea levels.. there should be closer bilateral ties with countries like Netherlands, which has been dealing with coastal erosion for hundreds of years their expertise and technology can do wonders to protect Bangladesh from further coastal erosion, your current barriers have failed miserably in many places and according to some of your experts it's just making the problems worse.