Given it’s earth 2 and we didn’t really much of Golden Age Aquaman I don’t mind whether he’s a full on villain or not. Lol same guy was the guy who would throw polar bears at people. That being said I definitely don’t see him being the full on antagonist might be more of a misunderstanding thing or be even held to the regard of Namor. Feel like he’d be showcased as a powerhouse in this case too if he goes up against the JSA