According to this page, it actually did stop at Troisdorf (though, that doesn't have to be correct). I don't see why they should have been able to stop at Neuwied but not any of the stations in between. Most of them are possibly too small, as the RE5 is quite long for a regional train, about 200m. The usual "RE" on this track, the RE8, is only about 110m max. Bonn-Beuel should have worked, though.
The connection in question is probably https://bahn.expert/details/RE28521/j/20251224-a0049123-9494....
According to this page, it actually did stop at Troisdorf (though, that doesn't have to be correct). I don't see why they should have been able to stop at Neuwied but not any of the stations in between. Most of them are possibly too small, as the RE5 is quite long for a regional train, about 200m. The usual "RE" on this track, the RE8, is only about 110m max. Bonn-Beuel should have worked, though.