Add a multitiered enchantment that can go on tools. Each level of the enchantment would increase the extra amount of blocks mined by 1-5 depending on how you want to balance it.

For what it's worth, this already exists in another mod.
https://www.curseforge.com/minecraft/mc-mods/vein-mining

AOE mining is something covered by the affix system (And is also an enchantment in that mod). So it's not something that will feature as an apoth enchantment.