MAGA acts a lot like one. This is based on my socially left and economically libertarian views. I am also 17 so I don't vote but these are my opinions.
Charismatic leaders: Trump's rallies are sometimes like comedy shows. They like to make people laugh at the Democrats and make fun of Biden.
Unquestioning faith: Most MAGA people I know are very close-minded and refuse to acknowledge any flaws in the party. They will bring up excuse after excuse so that Trump doesn't take any of the blame.
Isolation: In a way, yes. If someone went from MAGA to liberal and posted about it on social media, I can imagine the hordes of people going after them and telling them how dumb they are, calling them a libt*rd, or whatever insults they want to use. (This is based on my experience of having liberal views in a conservative family and school. I have some ethics-style classes and I'm usually on the opposing side of most people and the retaliation gets pretty extreme. )
Abuse: If anything, it's more emotional, but not too much abuse. MAGA likes to put its people on a pedestal and act like they're better people than liberals. (It's not the same for Christian MAGAs since they rely on self-hatred and guilt to keep people with them)
Authoritarianism: Yes, absolutely. Trump can be a convicted r*pist and have several felonies and people still love him. He can make r*pe-related jokes and people laugh.
No tolerance for dissent: From what I've experienced, yes. Refusing to acknowledge charges against someone proves this.
Secret knowledge: This by far might be the most accurate one. MAGA believes they're going to end the "deep-state", stop 5G, end cultural Marxism, George Floyd fake, end "woke", stop population control, or end chemtrails. Almost all of these conspiracy theories come from right-leaning people. MAHA also makes a lot of these theories to push people to vote for them. (soy boys, hormones in water, tap water makes your kids gay, kids are getting transitioned during school, or whatever else)
So are they a cult? By definition, it sure seems like it. If I could vote, I would have probably voted for Kamala since Chase Oliver wasn't likely to win. If I could have chosen Chase Oliver or Kamala Harris, I probably would have gone towards Chase Oliver. I think neither Kamala nor Trump are great, but Kamala is a much better person.