The Bosnian conversion to Islam seems to have been the result of special circumstances not present (at least to the same extent) among other South Slavs:
"Several factors appear to have been behind this process. Most important was that Christianity had relatively shallow roots in Bosnia prior the Ottoman domination. Bosnia lacked a strong Christian church organization to command a strong following—the result of a scarcity of priests and competition among the Orthodox and Roman Catholic Churches and the indigenous and schismatic
Bosnian Church, which collapsed shortly before the Ottomans arrived. This left most Bosnians religiously unengaged and receptive to the appeal of
Islam’s sophisticated and dynamic institutions. This receptiveness was aided by the development among many Bosnians of a kind of folk Christianity centered on various practices and ceremonies that was adaptable to a form of folk Islam popular at the time of the invasion..."
https://en.wikipedia.org/wiki/Islamization_of_Bosnia_and_Herzegovina