The information must flow from Carribean bank to Mexico, from Mexico to Italy, and then from Italy to Malta. And then Malta wants to know how much and where you made money in current and previous fiscal years so it must cooperate with the Carribean nation which in turn communicates to its private bank.
CRS only covers the first part, information exchange from the Caribbean bank to tax authorities of Mexico. The rest is out of scope of automatic information exchange and any further information flows require suspicion of crime.
CRS and TIEAs will not unravel this. You must butcher a few babies, smuggle drugs, or deposit at least 10M to spark interest for an in-depth international investigation of that scale.
Of course, if you can't tolerate any risk, declare and pay according to your local laws.
@xzars about your post in the other thread you wrote that under 10m it’s not good for the government to start the investigation, but in the case of ascertained crime it’s convenient for the government to start process by court? What are about the fees for an international process by court?