Only if you think the isolationist wing of the GOP is the party as a whole is this a betrayal. The old norm in American politics was that partisan politics ended at the shoreline and foreign policy was bipartisan. It served us well all through the Cold War (arguably actually WWIII, fought in slow motion thanks to nuclear deterrence, which we eventually won).
In fact, as a supporter of the old bipartisan foreign policy consensus, I think it easier to argue that the isolationist-let-Putin-have-Europe faction of the GOP are the traitors (possibly even in the strict sense of adhering to enemies of the United States) than that Mike Johnson has betrayed anyone. The time for a Russophilic foreign policy was the early to mid-1990's (when I argued for one), not now that having made post-Soviet Russia into a definitional enemy for no reason in the 1990's when we could have genuinely befriended them (even as the Allies made Weimar Germany into a pariah for the sins of the Kaiser and the German General Staff in 1914), a revanchist regime has taken over and made Russia into a threat to international peace once more.
Agreed. I understand the rationale of those people for whom not wanting to help Ukraine is based purely on fiscal reasons. I don't agree, but I get it.
But the whole tossing around of "treason" allegations based on disagreement on this issue is just nuts. It's also emblematic of why it is going to be so hard to build a majority.