[xCathedra]

I think your basically right, but the paradox actually makes more sense when you understand a few nuances of Protestantism:

0) Reformed (i.e. Calvinist) theologians made significant efforts to argue their understanding of predestination was not deterministic because humans are moral agents and responsible for their actions. They were aware and quite comfortable that God predestining morally responsible people is a paradox (technically referred to as an antinomy).

1) Reformed theologians also taught the predestined are 'born-again', meaning they are given a new spiritual life that changes that person's perspective and attitudes towards everything. The predestined evidence their salvation by good works.

Here's where the growth mindset would apply. Reformed theologians taught predestination as a motivating belief, rather than a fatalistic one. Grace, or salvation, in Reformed theology doesn't comes through religious observance but comes from faith, which demonstrates itself in how a person lives.