I liked it but I didn't get it.

Smile.

but look at all of the great normie memes it spawned

Most of it is taking the young part very seriously
Basically Lenny growing up and embracing the childish parts of himself that work and dropping the parts that dont
>Starts of childish and petty
>Not interested in doing work really
>Cuts himself off from the world (or the Vatican) in his room
>Overcompensates due to being insecure about papacy
Things that work for him and make him much more successful as a pope
>Embracing the love and peace he felt as a younger child before being abandoned
>Taking his way of explaining God to a child and explaining to everyone else
>His sweet but very innocent letters of love
>His juggling and other little talents
>Him not being over the top and revealing his awkwardness is even enduring and not a great flaw
>Embracing the kid saint's approach and just sending the message smile
Dropping the edgy child/teenage traits while keeping the loving innocent ones overall