This datapack rebalances mending to be harder to obtain by adding it to end city's (each chest is guarenteed a book, and it can be on random loot in end city chests) and stronghold library (randomly), it also removes mending from other sources outside of fishing, this also adds a Advancement for obtaining a mending book

Tested in 1.21.4, if you want it for any other version LMK and I'm happy to make it