Whether a libretto's source material is dull or not has little to do with whether the opera itself is dull. That has a lot more to do with the music. As well, Troyens is based on a small part of the Aeneid, and the libretto is by Berlioz, not Virgil.

And I was under the impression that you like Berlioz! There are excerpts and whole performances on YouTube, so you can judge for yourself whether you'd find Troyens boring. Start from the very beginning, would be my suggestion.

Whether you care to sit through the whole epic is another matter.