Mending Balance Idea - keep diamonds relevant

I checked the other "Mending balance idea" posts first, and I had not saw this yet, and I thought it was a good idea to kind of help balance mending and also keeping diamonds relevant as time goes on, since as it stands once you get a full set of mending gear diamonds are basically useless (minus use in decor?).

So, my idea is as follows:

Mending no longer works based off gaining XP to repair (all this really did was make you AFK at XP farms anyway).

Mending now counts more as a modifier, and less as a passive effect, so that the XP cost of repairing an item at an anvil is waived. This was the main reason mending was added to allow for you to keep nice pieces you work hard for, by simply avoiding the repair, and inevitable "too expensive!" repairs. By waiving the XP cost for repairs on Mending items it would both achieve the goal of keeping nice gear while also balancing the resource economy of the game. Also the increased demand for anvils would also mean that all the iron from iron farms has more purpose late game as well.

TL;DR

• Mending no longer adds durability from XP
• Mending now waives the XP cost to repair items with anvils
• Netherite repair TBD by devs, as this currently takes Netherite Ingots, and that cost might be too great (replace with diamonds alongside this change?)