Jordan played in the 90s.
Lebron peaked in the 2010s.
You don't compare current popularity between the two, but still Jordan would still win in a random international poll.
Lebron's popularity is measured in social media following and "clicks", Jordan's popularity is just unmatched. Honestly, since the NBA is "locked" now and can only be accessed through sat/cable channels and NBA TV, all of this is contained within a bubble of this fanbase.
I don't see NBA players appearing in ads in Europe anymore. I used to see Hakeem Olajuwon (Kellogg's?), Grant Hill (Sprite), Shaq was everywhere and so many others. You knew these guys even if you didn't follow the NBA. Now who's really famous outside of the NBA following? Anyone who dates some popular woman gets exposure to another part of the population.
I dare say that even within the USA the % of people who can tell who Lebron James is is definitely much lower than the equivalent of Jordan in his final season (and I'm talking 2003 here).
Media concentration also meant that everyone got the same exposure to news, just decided what they were more keen on. Now you filter out anything you don't wanna know. And guess what? A huge part of the world doesn't wanna know much about the NBA or basketball in general.
Lebron James has 160m followers in the age of Instagram. I dare say that at most x3 of that would be able to recognize him and x4-5 would recognize his name. Obviously that's a lot, but with Jordan that was definitely over a billion people at the height of his popularity and he's definitely 'immortal' in the sense that too many kids who never watched him know and can recognize him, because of the legacy or just the sneakers.
Lebron will never be that.
Think Elon Musk. Everyone knows the guy. You're in a cave, you've probably heard of him. That was Michael Jordan.
Ever heard of Nikola Karabatic? He's probably the greatest handball player of all time. You probably don't know or recognize him. Because you don't follow the sport. He's still the most popular guy within that environment. But if you ask someone who claims he follows several sports, he's probably never heard of him either unless he's into handball or at least paid attention to sport a couple of times in big tournaments.
Well, that's how the vast majority feels about Lebron James. Probably never heard of him if they don't watch basketball or stick when the sports news are on in May/June during deep playoffs/finals times, because honestly that's the only time most of the world shows NBA stuff. And that's not everywhere in the world, either.
P.S:
Not the greatest video out there but at least it's a basic example:
It's in Spain and basketball is probably the #2 team sport there.