Throwing it in a completely different direction (and no idea if this is of interest to you), but in a location where everyone can see everything through sensors long before it approaches weapons range, where computers can target and hit with perfection anything they aim for and where you can project such vast amounts of energy that they can destroy anything, you are not going to see all out combat.
Instead you're much more likely to get mental combat, misdirection, traitors, hacking attempts, and other sorts of subterfuge. The main goal in trying to destroy an enemy vessel will be in outthinking or removing the person in control of that vessel (and potentially any backup they have)
Rather than trying to hide your ship, you would try to either disrupt the enemy sensors (remember: everything they get is sensor input, there is no visual confirmation) or at least get them to think you have disrupted their sensors ("they can't really be coming in at ramming speed! he might be brash, but he's not crazy!").
Rather than trying to shoot a weapon towards them and hoping it hits, you might see a captain shoot a missile in a direction and try to then lure the ship to where it will detonate. ("they launched the MacGuffin towards that other waiting ship! We have to intercept it before they escape with it.")
Ships would come with a variety of weapons, but their use would be heavily improvised. After all; your computer can instantly predict where an incoming weapon will go, how to best avoid it or counter it, and react accordingly. A project traveling at relativistic speed means the opposing computer cannot determine where to shoot. So the computers would heavily cancel each other out.
That means that the options are either outsmarting the computer (which is basically analyzing, hacking or breaking it, most likely from inside the enemy ship by use of a saboteur or traitor) or outsmarting the person issuing commands to the computer in the first place (forcing them to make a bad move that not even a perfect computer can pull them out of)
It does allow for potentially interesting paths, in that there is very limited difference between a military vessel using a relativistic matter accelerator to bombard an enemy ship or a cargo vessel using one of its containers and a hotwired jump-engine to accelerate that to relativistic speed: either will completely obliterate the enemy; it depends on whether the military vessel's captain was lulled into a false sense of security or not whether he'll be able to foresee and evade such a "weapon".
Combat between vessels would be mostly determined by a combination of the best gear and also the smartest, quickest thinking captain and understanding your opponent the best. Large fleets would be rare (too many points of failure) but colorful characters manning ships would be common (because discipline might actually be detrimental, as it is predictable)