The next step for Disney is to make a Jesus movie and start collecting royalties on sales of the Bible.
https://www.simplybible.com/f744-revln-seven-powers-of-chris...
Jesus as Superhero is a common Christian theme:
https://duckduckgo.com/?q=jesus+superhero
But they'd have to either treat him as a Mary Sue, and be boring, or make him a character with human flaws, which would offend people.
On the other hand, if you go onto the dark side of YouTube, there's a guy named Professor Geek. His traditionalist views on mythological heroes and opposition to the injection of current-year politics into modern mythological media like comic books automatically make him a mouthpiece of the alt-right and anything he says is not to be trusted. But should you trust some of the things he says, there are interesting perspectives in his videos on the two major types of hero: the aspirational hero, a character representing an ideal to be striven for; and the cathartic-motivational hero, a flawed character who is struggling to approach the ideal. Think Superman and Batman.
Jesus is clearly supposed to be an aspirational hero. His story is not supposed to be that of a flawed person struggling to be better. He is a template to show what a good person looks like: become more like Jesus, and you will be better. The Christian answer to the cathartic-motivational hero is Saul of Tarsus. Maybe some of the Apostles also count.
So even though I personally find Jesus boring (and this was a factor in me renouncing my Christian faith), the Jesus narrative does serve a mythological function.
This story has everything a Christian could hope to be. Accepting Jesus, Jesus as the ultimate human, repentance, and the forgiveness of once sins.
So, no, this is in the controversy you think it is.
https://web.archive.org/web/20210409183213/https://www.redbu...
And while the design itself is ambiguous, I'll note that the t-shirt tags specifically include "marvel t-shirts" in the list, and the All Product Tags list includes "marvel" as well.
That would seem to contradict the idea that this was intended to be a reference to the Gaiman character.
Edit:
A commenter below noted that the person's profile picture, which includes this t-shirt, clearly references the Marvel character as well:
https://pbs.twimg.com/profile_images/1337356777113985024/e-a...
So no, I think you're mistaken and this t-shirt was a reference to the Marvel IP.
Marvel has never referred to their Loki (at least in the movies) as "Low Key"
Edited to add: Note that I think there's very much a good argument to be made that this stuff does or should fall well in bound of what fans can do in referencing a work, I just think that "it's not even the same character!" is off base.