Overview

Presently, the only way to acquire Excavation-ready tools is by either applying the TiC modifier, or by using the equivalent enchantment on other tools.
The enchantment cannot be acquired though any means (Table Enchanting, trading with villagers, loot chests in structures), other than with the EnderIO Enchanter. To get the enchantment, you need to provide the modifier used for TiC tools.
This is a problem, because the Modifier requires Manyullyn, which is a resource that can only be gathered if one has infrastructure in TiC already. When using the TiC modifier this is an effective gate to prevent getting powerful tools too early, and it's a cost I support.
However, when using other tools, this requires doing a mod you may have otherwise avoided or not bothered with, which is an unnecessary cost when one already has infrastructure in different systems for upgrading tools. There needs to be a way of acquiring the enchantment for other tools without the TiC modifier.

Proposed solutions

• Regular Enchanting

  It could be possible to simple add the Excavation enchant into the regular enchantment table, at about the same rarity as Fortune or Silk Touch, and have it be subject tot he normal rules of enchanting. This means players who have invested in non-TiC tools can approach the enchants like they approach other TiC modifiers like Hate and Luck in the exact same way.

• Treasure Enchantments

  Treasure enchantments cannot be gained from the enchantment table, but can be found in chests and traded with lucky villagers. This would put the Excavate I-V enchantments on the same value as Mending, Frost Walker, and Curses. It would also be recommended to add the book to the loot tables of structures such as End Cities, where the player is expected to have significant footing in the "Vanilla" game.

• Adding an alternative recipe

  The easiest solution may be to add an alternative recipe that does not cost Manyullyn, instead replacing it with diamond, emerald, or another valuable resource that competes with Manyullyn. I would also recommend replacing the slime in the recipe with obsidian, which guarantees the option is both less attractive for TiC users and more attractive for vanilla-style users, as well as gating it off from being rushed.

Will be looked at in a future update