You are absolutely correct. Directed energy beams are just as much a bust for space military opera as 'energy shields'. In all of the tests of directed energy beam weapons, the best the US army has done is to put holes in the target. There just isn't enough energy in a directed energy beam to do much damage. Certainly not enough to cause a space battleship to be completely destroyed. Like using a laser pointer to 'destroy' a drone.
And there would be no need for shields. Plating and other such coverings on space ships would be much more effective, as well as being passive. 'We lost power to the shields, captain!' just doesn't cut it in warfare. But special reflective coatings, materials with super efficient heat transfer abilities, special hardened plating against radiation (lead as an example) don't suffer from power loss, and would be much more effective, making directed energy beams pretty much useless. At best, 'shields' would be surface charges on the outer skin, sort of like an electrostatic surface charge.
Kinetic weapons will always win out. Less dramatic, but more effective.
So why do sci-fi writers insist on using them?
Perhaps because of the very false belief that exploding percussion weapons don't work in space. The explosive gasses and materials from the explosion don't just vanish, they continue in a 'wave' of energy equivalent to the original energy of the explosion. 'Shrapnel', if you will.
And maybe because of the problems with targeting projectile weapons. Space is huge, and so the battling space ships would have to be very close together in order for evasive action to not be effective. A 'speed of light' weapon is always much more dramatic and immediate than the slowness of space missiles. Imagine how boring it would be if the antagonists had to wait fifteen, twenty minutes for the missiles to get to their target, which of course would no longer be there? 'Fire missile tubes three, four, and five! Now, go for a coffee break and wait to see what happens!' just doesn't generate a lot of suspense. Yet, even directed energy beams take time to travel through astronomical distances.
Or more specifically, a 'space military opera' wouldn't be very entertaining without huge battleships, and even bigger explosions. The stories are written for us earthlings, who think about space warfare as simply naval warfare translated into space. Huge battleships facing off against each other. But it is more like air warfare. There is no advantage to huge 'battleship' fighter planes. Smaller and more maneuverable is better than huge, ungainly and easily targeted blimps.
But my money is on the simple point that space military opera sci-fi writers in general are just not creative enough (lazy?) to think of anything other than the 'same old same old' stock-in-trade directed energy beam weapons. The readers accept it, the writers need to churn out their works quickly, and so they fall back on the same tried-and-true memes. No need to be creative, when you can fill your story with mega explosions, fancy energy beams, impenetrable shields, and huge ships blowing up with loss of all lives and the book will sell.
But the truth is, real 'space warfare' if it ever happens will be boring, slow, plodding, and 99.99999% uneventful. Not really the stuff that makes for good high-suspense action-packed seat-of-your-pants fiction.
So, sci-fi space opera warfare will continue to be energy beams and 'shields up' and huge battleships exploding in space, with the reality hand waved away.