In Minecraft, finding Lapis tends to be more difficult I find for the rate at which it’s consumed, while diamonds and their tools last so long with enchantments that you generally don’t need anywhere near as many as you’ll get from bottom layer mining. Lapis is as common as grains of sand in the middle east, and it is less useful than a snapped lockpick. It isn’t as valuable, by the very nature of it’s frequency and utility. If it wasn’t for mending, I’d break my diamond unbreaking 3 stuff all the time. Lapis is only used for using the enchantment table, which becomes obsolete as soon as you have a villager trading hall set up (or just the tools that you need with mending on them). Diamonds on the other hand are used in quite a few crafting recepies, and are much less common. After one mining trip I usually have about a half a stack of lapis blocks, while my best haul of diamonds was about a stack.
The thing about mending is that you can only get it through books, which are either rare loot or spawn as an enchantment on tools in end city chests. Or, you can just get a villager to sell one to you. Basically it makes your tools and armor indestructible if you have a reliable way of getting EXP. I only play vanilla on my realm. Abusing mechanics is unironically the endgame of Minecraft. How else are you going to sustain your massive builds/farms?