Democrats, Republicans and MAGA.

MAGA isn’t even a faction – it’s just a Trump campaign slogan. If you mean that there are nativists who complain about immigration, sure, but those have always been around. This isn’t even a particularly notable time for them; the Know-Nothings or the anti-Chinese riots back around 1870 were considerably stronger.

MAGA is not centrist or big-tent and there are enough of them that can break things or hold hostages or say elect a religious lunny to be speaker of the house. They cling to extremist positions and absurd conspiracy theories, and attempt to force their will on to others.

As to the conspiracy theorist stuff:

Being a big-tent party means that one has to suck in all of the voters from a broad range of areas. Both the Republican and Democratic parties are gonna include groups of voters that have views that are kinda out there. But that doesn’t mean that that’s what winds up being adopted as policy. The conspiracy stuff isn’t new. There’s been a conspiracy theorist crowd going waaay back into US political history. If it were the 1970s, the right-wing form would be something like the John Birch Society.

They do not want to fund Ukraine for, some reason, and presently they are winning on that.

What you don’t have is terminating Ukraine aid being the centerpiece of any political campaign. Donald Trump’s campaign website doesn’t even mention Ukraine on its issues portion. The only reference to Russia on said page is about how Biden isn’t tough enough on Russia and how Trump would take a harder line on Russia. There’s no overwhelming opposition to supporting Ukraine in Pew or Gallup polls, and foreign policy doesn’t usually rate all that high in importance anyway when it comes to US domestic politics.