When you say Mbappe is better in terms of performance, it's quite natural, because the age is also very different. If you say Messi is better in terms of individuals, this achievement is also reasonable because he is nearing the end.
And by age 23 he already achieved more than what Mbappe did, and by 35 or so Mbappe will probably not have what Messi has neither. The type of dominance Barcelona had for a while is the key to what Messi did of course, and Mbappe doesn't have that because with all the money in the world you could not build a La Masia and players like Xavi and Iniesta and Puyol and Pique, and many others who contributed to Messis amazing career.
Breaking Messi's records may not be impossible for Mbappe. But it is very difficult. Messi probably won 4 Ballon d'Or at the age of 23. But Mbappe has yet to win a single Ballon d'Or. Messi won 7 Ballon d'Or. Can Mbappe win 7? Mbappe, on the other hand, has already won the World Cup. But Messi could not win the World Cup. If Messi can win the World Cup this year, he will be considered as the great player of all time.