The Covenant (Halo) vs The Grand Imperium of Man (Warhammer 40k)

[The Glyphstone]

The Rogue Trader sourcebook mentions it over and over again- because Lances ignore armor, and Void Shields block anything, they use projectile weapons to soak the shields and then fire lances to ignore the hull armor

Indeed.

And yes, there do exist energy based non-lance weapons, but they are rare (typically mounted on Adeptus Mechanicus ships who can experiment with the weird stuff, or lost archaeotech ships), and usually shorter-ranged. The exceptions are xeno-tech weapons (Eldar use energy weapon batteries instead of projectiles), but that wouldn't be found on Imperial Navy line vessels.

Ships with lance-only or lance-heavy armament aren't typically standard line vessels either. They're purpose designed that way, to move in concert with other ships carrying a heavy or pure projectile armament.