The R majority is so small that they need the MAGA wing to vote for every single thing they want to do to pass a republican bill.
The MAGA wing do not want any more going to Ukraine, so the first thing they will do is they will tell McCarthy and his traditional republicans that if they start tabling more support bills for Ukraine, they will boycott votes of other republican policies.
So the R’s will have to choose between advancing their political goals or helping Ukraine and they’ll choose self interest every time.
Not just that, as part of their “negotiations” (blackmail) to get McCarthy elected speaker, he changed the rules of the house so that all it takes is ONE member to call a motion to vacate and trigger vote on removing the speaker.
So if McCarthy ever crosses the MAGA lot, they trigger a vote to remove him, vote with the Democrats to remove him, and then we go back to the situation 2 weeks ago where there’s vote after vote after vote to elect a speaker which they can’t do without the MAGA bloc, and so they have to concede everything to them.
That is assuming that not tabling more aid to Ukraine was not a part of the secret negotiations to get McCarthy elected 2 weeks ago, which it could easily have been given Gaetz and MTG were laughing about how they were scratching their heads to think of more things for McCarthy to promise them in return for their votes.
So sorry to say this, but they are in control, not Kevin McCarthy and the “normal” republicans.