The [Friendship] Between Heaven and Earth
Strengths: Unparalleled Biological Manipulation, High Ship Redundancy, There are many of them, [Friendship]
Weaknesses: Slower than you, Less maneuverable than you, Sensors by-and-large detect via organics, FTL is worse (shorter jumps, can't be used in system, travels on the same vector as the ship is at sublight speeds.), Long Term Endurance is worse (need to resupply), integrating new technology is...troublesome, have never fought a proper war in space, are bad at large scale organization, currently have their entire expeditionary force in one big basket, slow firing rate, variable defensive abilities.
I too based the Uelewa offensive capabilities around the concept of a Wave Motion Gun (long charge time, one target), but it isn't much more destructive than y'all's weapons. It's main advantage is that it's a very exotic energy, and rather than a beam is more of a cylinder of space that fills with this energy, before it's all shunted away from the Uelewa, so in effect it is an armour piercing weapon. Shields prevent the buildup inside the shielded area, but it is energy draining. It's also pretty short range, compared to most space weaponry.
In the rare occurrence that the battle is in interstellar space, and you happen to position your ship at exactly the termination point of the cylinder, the Uelewa speculate bad things would happen to you as it rips a large tear in space-time, but they've never actually seen it happen, nor can they aim it to specifically encourage this effect (alas, they have no computers, and the input of energy is not-always consistent for reasons.). I'm not expecting to actually use this in the RP, I just wanted to mention it in case someone deliberately goes out of their way to fulfill the needed criteria of going through the bother to run into them in interstellar space, antagonize them into a shooting match, and then position some ships just at or slightly beyond their observed range instead of lobbing guided missiles/Kinetic weapons at them from very far away.
Tl;dr The Uelewa are bad at everything except the equivalent of a space knife fight and [Befriending]. Nuke them from orbit, nuke them from far away, you're golden.