Yeah I think your assessment of how the Indonesian government would respond to any suggestions of ex situ conservation re-efforts with help from outside organisations is very likely exactly what the situation at hand is with any attempts now to pursue alternative conservation efforts outside of Java, Sumatra and Borneo.
It's so despairingly frustrating though hey as like you pointed out, looking at what happened with the last remaining northern white rhinos in central-east and north-east Africa, now gone from existence, but watched go every painful moment of seeing each individual at a time (credit for the many people almost entirely unacknowledged, who were involved in trying to save the remaining few from extinction though, sadly it still happened; underfunded and underresourced work imagine was the case, and probably only able to start largely after years of campaigning for the need for by many of the same people who tried really hard to save them).
