anime

Ok, for the most part your definitions aren't unreasonable, but

To me, explicit means that it could not fairly be interpreted through the lens of liberal ideology.

is gonna be an impossibly high bar to climb, because capital is nothing if not famous for subsuming critiques of it into itself. And we're also going to run into a particular snag with regards to Mobile Suit Gundam because of, um, the history of Left-wing movements in Japan.

The reason you'll see people say that Gundam (and shows from around that same era like Nausicaa and Space Battleship Yamoto) have left wing politics embedded in them is because their creators were involved in Left-wing student movements when they were young, and those politics leak through into their work. Here's an excellent primer I found on Zenkyoto (the Japanese New Left) and it's influence on Japanese pop culture, I strongly recommend you give it a read before continuing because I'm not sure my takes here will make sense without that historical context.

With regards to MS Gundam itself, I think it's important to keep in mind that it was a piece of media written by survivors of WW2 explicitly designed as an anti-fascist work first and foremost, and...... then also to sell plastic toys to children. So you'll get really thoughtful episodes about how fascism gets ordinary people on board with it by building a false class consciousness based on imagined hierarchy's, or how cycles of violence perpetuate those fascist lines of thinking, or how in the end only the working class on both sides is actually hurt by the war, in storytelling and messaging that isn't liberal both-sides equivocating but just a straight up condemnation of fascism as a concept, using analysis that's more Marxist than anything. But also, Pew Pew Laser fights with Giant Robots.

Granted, the show doesn't explicitly advocate for communism, but the idea of Newtypes, a new generation of youth capable of empathy so great they can read minds and communicate directly to each other as equals, being the only people capable of ending the war and bringing about a better world betrays at least some of the the creator's socialist leanings at the time, at least in my opinion.

(Also, just as an amusing sidenote, Char's popularity probably has less to do with him being the charismatic anti-hero and more to do with how much thirsty cis-women really wanted him to bang Amuro in gay fanfic that's almost entirely disconnected from any official narrative.)

With Zeta: the main character is a student who runs off and joins a paramilitary organisation in order to conduct a guerilla war against a fascistic occupying imperial power, and Char comes back as the second coming of Che Guevara. Zeta is absolutely a commentary on Japan's role post-WW2 in America's Empire, and shouldn't need much elaboration, since it practically starts off as a romanticized leftist student's escapist fantasy (and who could blame them, as a student in the 70's who wouldn't want to run off and join a guerilla war with Che). The Federation Operation Paperclips it's own Zaku's and is basically running it's own Project MKULTRA, for crying out loud.

But here's the snag.

See, the Japanese New Left was crushed by the same forces of neoliberal capital that crushed left-wing movements across the world- it was crushed by Reaganism and Thatcherism and the LDP. The reason the student activists turned to art and film, started writing their own Sci-fi tv shows and movies, was to channel their frustration at failing to build a better world in their own time, and spread their ideas to a new generation in the hopes that they would pick up where they left off.

In Zeta, the left doesn't win because the left didn't win in real life. All that was achieved was to kick the can down the road, at great personal cost. "We stopped the Imperialist Fascist Military Industrial Complex, temporarily. Yaaaaaaay."

So, how do we evaluate works like these? Can a piece of media be truly "leftist" if it portrays the defeat of the left, since that just furthers Capitalist Realism? However, at the same time, if it's reflecting a historical reality in it's fictional setting, can we safely dismiss it if we're historical materialists? Again, I don't necessarily think that your definitions are unreasonable, but I think we should allow for the historical context and some levels of nuance to speak for themselves here.