Your scenario doesn’t quite fit. In most cases, the local state process requires delegates to be bound to a specific candidate on the first ballot. So your “diehard Trump supporters” are free to vote how they and/or their constituents support on any subsequent ballot. In my view that’s fair. Because if all delegates are bound on all ballots, there is no way to select a nominee if no candidate won a majority of delegates during the primary.
The beauty of our republic is there are 50 sovereign states and a few territories. All of whom would not send 100% Trump loyalists to the GOP convention. Especially if the popular vote was as you described.
The last line of my prior post nailed it.