i actually think jedi survivor handled the dark side really well tbh, both narratively and as a gameplay mechanic.
I dont think cal in survivor is just dipping into the dark side for a force boost, hes clearly struggling with sticking to the light because of all the pain he carries and the people he keeps having to kill.
like at the start with the inquisitor he gave her a chance to surrender but his heart clearly wasnt in it and he had already resigned himself to killing her. His crew had just died and hes been fighting the empire for five years without any progress. Then when he gets to koboh, reconnects with greez and cere and merrin, and finds out about tanalor, he gets his hope back. Rayvis and dagan gera oppose him, and he struggles with the need to kill them. He kills rayvis because rayvis wanted him to and flat out refused to surrender. It is against the jedi code to kill a defeated opponent, but it was against rayvis code to surrender even when defeated. I think cal saw it as justifiable in a way; it is less an execution than the fullfilment of a wish. And also, cal needed to do it to get to dagan, so there was an ends justify the means aspect to it.
That line of thought gets carried over to dagan gera. Cal really wanted to work together with dagan in restoring the jedi order, but dagan wanted to build an army, cal wanted to build a refuge. He didnt think he could beat dagan and so he panicked and used that panic as a source of power. He used the dark side to get a power boost, and of course he knows its wrong, but it was only for a moment, and again, sometimes the ends justify the means, right?
Now having access to tanalor, cal returns to jeddha, bright and hopeful, only to get betrayed by a close friend. To make things worse, that friend reveals himself to be a jedi only now, only when using his abilities to stab cal in the back. Cal loses cere, cal loses cordova, cal loses bode, cal loses tanalor, cal loses the jedha archives, and cal loses himself. He tracks bode down and he is furious and in pain. He finds a little girl in an empire base, and part of him thinks, wait, what am i doing. He tries to give bode another chance, but when bode betrays him again the anger comes back.
And honestly, i think this may have been planned since fallen order in a way. In this part of the game, cal's force freeze becomes a force rage. As a gameplay mechanic, the force freeze worked like a panic button in jedi survivor. You fill up the meter by fighting and use it when overwhelmed by enemies, to escape or when you need to quickly deal a lot of damage. It is not an ability used when cal is calm or mindful or whatever you call it. It is an ability used out of desperation. This is also reflected in its background. The first time we see it used in universe is kylo ren in TFA iirc, and the first time we see cal use it is during order 66. I dont know if its a dark side ability per se, but for cal it is something born out of trauma, so for it to evolve into a full on dark side skill is not that surprising.
Anyway, to move on with the story, after meeting kata cal does calm down somewhat in regards to bode. Before that he really really wanted to kill him, even merrin calls him out on it iirc. But when following bode to tanalor cal gives him chance after chance after chance to surrender, to work things out together, despite his massive betrayal. Cal is desperate for a reason to spare bode's life, but bode just keeps refusing every offer. As the fight goes on, bode hurts both kata and merrin. Cal shoots bode. Bode is down on the ground, wounded, but (and correct me if im wrong here its been a while since i played the game) he grabs his blaster and tries to shoot cal but the blaster malfunctions or something. So even when he is defeated he tried to kill cal, but now he is truly unarmed. For a moment, cal thinks and considers sparing him, but then his face hardens (he might have looked over to merrin?) And he shoots bode. Could he have spared him, imprisoned him and maybe redeemed him? we dont know, and well never know. Cal killing bode was not an act of self defense or a defeat of evil, it was the execution of a defeated opponent to prevent him from potentially doing further harm, and you could give plentt of reasons for why this is justified and all, but that doesnt take away the fact that this is definitely not the jedi way. Literally everytime a jedi did (or was about to do) this (mace and sheev, anakin and dooku, luke and vader) this was portrayed as wrong. This is cal slipping in his code. I dont think the game is just using the dark side as a temporary power up, because by the end of the story cal is still struggling with that darkness he invited.
I think Jedi 3 is gonna get deeper into cals psyche and his (very reluctant but still there) use of the dark side. I dont think hes gonna Fall, but either he pulls himself back to the light or he'll give up being a jedi (or he'll die but i hope not)