Why I fear this won't go well for her?

And cue next scene gantus barely phase and goes Itachi on her. Though truefully I hope she pulls a win

It won't end well.
This the end of the road.
She fell for Gantus provocation(carefully planned) and she attacking even knowing that he is stronger than her(remeber she was searching Debbie help to defeat him at the begin of the story, she know she can't take on Gantus alone).
And from all we see Gantus know her way too well. (Seriously it surprsingly how good at psychological manipulation the bad guy if FFC are.)

😠Prepare to feel the thunder Gantus.

why do none of you have faith in Kalita?

Because if the character you're just getting to know defeat their Big Bad Arch-Nemesis in the first act then there's not much of a story to tell is there? =P

Also keep in mind this is before she crush on Muko and Cookie and accept their challenge...So we know that thing did not go as Kalita wished for and she get out nearly broken inside from it.(at least till a certain silly bunny german supplex hope for the future in her stubborn skull)

And here we go, the beloved thunder fist vixen against... The emperor? Is that what he make himself called? Humble guy...

Round 1... FIGHT!

but seriously I can see what her old friend/leader was talking about

Why do I have this feeling that, no matter what will happen, things are just going to get worse?

SMAAAAAAAAAAAAAASH!!!

Wow, Kalita went all out with the technique she used to defeat Muko in one blow. Something tells me it won't be enough to defeat Gantus though.

I just now noticed....Leyline is the only one not surprised at all by the events. Seem that the "queen" of the gang is fully aware of the plan to get rid of the rabid vixen and the result of it.(suspect reinforced by the fact that Gantus seem aware of lot of stuff about Kalita that only a once tiem close friend like Leyline could know)