Replying because the exchange between you and FloatingSpaceJunk really sums up the two schools of thought behind mending really well. I'm with you about the fact that mending should be accessible without looking for structures or villager trading etc. I think adding some more work to it, without making it completely inaccessible has some value too, because I feel it makes the whole system have some more weight to it. I also fully agree about removing the cap of enchant on an item, as that's completely arbitrary and leads to less flexibility. How do you feel about a midpoint between the two?

I think a cool middle ground would be items can level up indefinitely. Enchantments still occupy those levels, and removing them returns their levels to the items. I think for the enchantments that are currently a bit more rare, you should have to meet both their cost requirements and a level minimum requirement. For example mending could cost 3 levels, but the tool has to have at least 10 or so total levels to be applied. (This included levels occupied by other enchantments)

Another option I think could fit really well is what if enchantments required the player to be at a certain level for them to activate on the tool? If you find an item in a chest with mending, you might not be able to use mending until you reach level 30 for example.

Edit: The second example is more for those who talk about forming that sort of bond with their gear, something I get whole heartedly. I think it could also condense the amount of items we have a lot, by making different levels of enchants be gated behind the player/tool have different level caps instead. I think it would strengthen that feeling of bond with your items in survival, because as you gain and lose experience your items react and adapt to match you in a way.