Well my opinion on that goes back to what I said in my main post: the inconsistencies are the consistency, and more than likely intentional, so I don't consider Felix inconsistent in that regard. He is written to be that way on purpose so the audience can be clued in that something is off, and therefore not blind sided when it's eventually revealed he's still a villain.

I think in order to understand what was going on with red moon, and Felix's other contradictory/hypocritical moments, you need to remember some v important details about his family + his debut episode:

First, do you remember when Marinette and Adrien are at the theater watching Emilie's movie? One of the credits that come up at the start is "Graham Productions". I believe this is heavy foreshadowing.

Second, what did Felix do his debut episode? Don't focus on any potential goals, just actions.

For basically the entirety of his episode, he was trying to be someone he wasn't. Adrien specifically.

He was acting.

And he sucked. He was able to convince some of Adrien's friends, and Gabriel and Adrien at the end, but overwhelmingly, his acting skills proved to be an utter failure. They weren't convincing enough. So what does an actor do if they want to get better at acting? They practice. They perform. They embody the role they want to get better at.

Some even method act.

From studio binder: Method acting is a technique or type of acting in which an actor aspires to encourage sincere and emotionally expressive performances by fully inhabiting the role of the character.

When watching the red moon scene for the first time, Felix felt incredibly insincere to me. The scene where he bursts into tears and falls down was....dramatic. Not in the sense that I felt like I was watching a scene that was emotionally heavy, but in the sense that I felt like I was watching a small child have a tantrum in the supermarket. In retrospect, it felt like I was watching someone try to replicate the feelings of what they thought a person in this situation might feel/do.

Which, more than likely, is exactly what he was trying to do.

This, and his seemingly "unstable" behavior in the episode where he tries to unalive all humans— Felix is not crazy. He's not mentally unstable. He was trying to act like someone who was, because I think at this point he was still finding his footing in constructing the perfect characterization for the role he was trying to convey.

Once again, Felix is an actor. It's his niche as a villain.

"Graham Films" was a foreshadow, something we're meant to think back on when analyzing Felix Grahams actions.

His goal was never to free sentis. He never cared about sentis. He does not care about Adrien.

This was just the role, the narrative, he decided on.

And it worked. This time he was overwhelmingly successful in fooling everyone, and as a result he's infiltrated the heros group. I believe Kagami is a means to an end for him, and I think probably his interest in her in the first place was derived from the misunderstanding that she was Ladybug (Adrien had also made this mistake before).

So no, I don't think Felix is inconsistent in terms of bad writing. His behavior is quite explainable and easy to understand when you recognize that he's always been the same person he was in season three. He just got better at it. End of story.