Instead of making it hardcoded and only work for vanilla things

my current plan is to check if the block is a 'compacted block' where the block can be broken down in a 1-item shapeless recipe or if the block is an ore (not sure how best to do this, perhaps by checking for smelting recipies? not all ore is fortune-able or drops something other than itself)

:concern: I'd say you should probably just implement a json thing instead, hardcoding things may lead to... quite undesirable results honestly.

I second this.
Having things based on Loot Tables would make things easier to modify with datapacks.