Going through Episode 5 has been an absolute slog. Enemies seem damn near unkillable, and it takes me an hour on average to take out a story boss. Most recently, the game has introduced Resta Golems and Sorcers which heal for such an overwhelmingly absurd amount that I can't make any progress at all without the help of a photon/dark blast. I wanted to see if other people are having issues with the story mode combat or if I'm just doing something wrong build wise. My damage doesn't appear to be lacking in any capacity anywhere else in the game, it's strictly in Story Mode where I don't appear to be doing anything...

You don't have to do Hardcore difficulty to progress.

Yeah I go casual to unlock features and catch up, then when i'm ready I do the hardcore stuff.

If you want to just get through story then yeah, go with casual mode for the fights. You can go back later for the star gems and titles.

With Casual being the exact polar opposite and being entirely too easy to complete I'd prefer to do Hardcore. I mostly just needed to know if the problem was something I was doing wrong, or if the enemies being nigh-immortal bullet sponges was an intentional in feature.

What is your class (main class, subclass), and your equipment/level?

If the enemies are too much of a damage-sponge for you then it may have something to do with your equipment not being sufficient or your playstyle may be lacking in the situations you are in. More details would help me provide a better answer but so far it sounds like an issue of being undergeared in these fights.

In the case of Episode 5 the game starts a very heavy transition of moving away from sheer equipment power (though it still helps) and starts to push players into being more reactive, faster, and more "flexible" at handling multiple scenarios for combat to which not every class can easily adapt to.

I did the entire episode 5 in Hardcore and the only issue I had was with Double/Gemini fight because too much mobs that keep spamming all the time and is a small place to fight, the only thing I can say from all the fights is don't stay still ever the hp of the mobs is not the issue is the quantity so mobility is highly required in this episode and even more in episode 6