You're quite right with the first bold bit.
Second bit "no one comes close to Messi.... etc, etc....". So Messi has scored more club goals?, Messi has scored more international goals?, Messi has been playing (for a "top club") longer?, Messi has more international tournament medals?
Second bit is about if we're talking about facing all angles of what a player needs to be consider the greatest one.
Maradona - Epic WC performances, wonderful skill, international success, turned a team into league contenders - Lacks scoring, European level titles, a longer and stable career (if we take Ronaldo/Messi as staples, with 10+ years in their legs being top 3)
Pele - The greatest from every POV, but the Euro-centric view in football today will hurt his legacy, even though probably South-American football was better or equal to Europe (shared dominance of the Intercontinental with Real and Inter for a decade), has everything else in spades (skill, goals, longevity and titles at every level)
Di Stefano? Similar to Di Stefano, he had everything too and even won an international title, but no World Cup appearances hurt his legacy
Cruyff - Another insance career that covers all bases, we could even "forgive" he never won an international title because at least he played in a final, but if we're not going to fogive Pelé and Di Stefano a single stain, we can't do the same with him
Messi - Up there with anyone else in every term, except, like Cruyff, lack of international success, you can argue he never won a title with Argentina BUT he played 4 finals, and then you could also argue that he lost 4 finals.
Cristiano - Same as Messi, he has won indeed a Euro, but he's also the only one in this list that never played a WC final, and we're not forgiving anything to anyone, he's also regarded as the less "skilled" of all these guys by people, even tho his output is better than almost all of them
Then there's the outlayers that could have a chance to get there, but never were in the talk.
Müller - As successful and impactful as everyone else above, won every title, won some of them various times, yet I've never seen him in the GOAT talk, and I guess it's because lack of that "magic" skill
Beckenbauer - Another one that has it all and could be a fair shout, but basically a defender, no defender will ever be in the talk for the GOAT throne
Ronaldo Nazario - As always, he's the weird one here, his career wasn't consistent, but it was indeed long, lacks European level success (neve won a UCL), but had skills, goals and international performances to bore us for a couple days.
Zidane - WC Winner, European success, but his lack of what almost everyone on this list has (goal) hurts his chances, that and those years in Juventus after Del Piero's injury (personal opinion, Zidane should've done better there, he basically lost his chance to the throne those seasons)
Xavi and Iniesta - No one talks about this, we all know what they did with Barcelona (and most people think thanks to Messi), but they translated that to the national team, probably the most influential duo in he story of football alongside Gerd/Franz, but their lack of goal product will secure they're never there (that and sharing a locker room with Messi)
Key part here is, the greatest ever debate never was a fair fight, as someone raised in the 90's and fully understanding football through the 00's the talk was always about Pelé and Maradona, but if you look at it with a cold head, Maradona had no business being there if the standards he was subject were similar ti what we ask in this era, then Müller's lack of flair or that magic connection Maradona seem to have with a whole country would be less important.
Personally, now here, thinking carefully about it and today (I might change my biased opinion), Pelé should be the absolut king of football, he was a flair player as the best ones (Cruyff, Messi or Maradona), he scored like the greates ones (Messi, Ronaldo and Müller), had a career as long as anyone but won most titles than almost all of them combined, especially World Cups, Brazil was loaded in that era?. Probably, but also Barcelona and Real Madrid and we keep praising Leo and Cris, when we put them in worse squads like Portugal or Argentina the evidence crystal clear.
The fact that Pelé isn't considered the best without discussion anymore is because most of us think of South-American level as a joke, but it wasn't that way in his era.