I mine copper, iron, and diamonds with a Silk Touch pickaxe to save inventory space.
The bot currently only tries to pick up raw copper, iron, etc but doesn't path find to dropped ore block.

I also looked into itemFollowing, but it doesn’t seem to exist anymore.

Maybe add this feature back in to let the bot pathfind to wanted, dropped blocks.

You could maybe implement this by letting the user configure which blocks the bot tries to pick up when mining a block. For example, if the user wants the bot to pick up apples when mining oak logs, they just enter a command that might go like this:

#minerule add minecraft:oak_log minecraft:apple