Mending & Unbreaking Revamp

I think everyone can agree that Mending in its current iteration is a problem, as it is very easy to aquire as well as makes the creation of new Tools obsolete aside from potential backup tools when dying in the void (or lava if not netherrite).
Thats why I would like to propose a change to Mending as well as Unbreaking, as my idea for Mending would be too similar to the current state of Unbreaking.

Unbreaking: Instead of reducing the chance of taking durability damage, increases the durability of a tool, weapon or armor by x% * EnchantLevel.
With x being the base durability of said Item. This change is really basic and doesn't touch the mechanic too much, as increasing the durability is essentially the same as decreasing the chance of recieving durability damage at all.

Now for the main change:
Mending: Instead of "healing" the tool by collecting XP there could be chance of recieving one extra point of durability back when recieving durability damage. 
This is much easier to balance as the chance can be actually be changed and this would also open the chance of tools, armor and weapons actually breaking in the normal gameplay loop.

The chance of gaining durability back could be dependend on the Mending level or the number of durability points could be increased by that.

This would also add an extra level of difficulty in getting "perfect" gear as one has to put more books on an item and therefore increase the chance of not getting everything on there.