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This is something that can't be done just by changing some variables. (Well... actually... it could but you would need to change more than 500 values, and nobody got time for that)
So the easier step is to edit the datapack. You will need to know what a block tag is though. If you don't know that, you might want to read the wiki entry about them. You'll also need a Texteditor, like Notepad++, Sublime or Visual Studio Code. Then you need to unzip the datapack. The Software WinRAR or 7zip can do that. The filestructure can be seen in the following and the folder you'll want to have open is the one for Blocktags.
The important Ones are highlighted in red. The .json-file "pickblocks" controls what Blocks can be veinmined by a pickaxe. The other highlighted blocktags correspond to the other Tools and what Blocks they can veinmine. The tag "alltools" lists Blocks that have no assigned tool or which can be broken by any tool where it will count as having used the tool. This is important for knowing when the player breaks a block. The Ores have the Pickaxe as an assigned Tool, so the file "pickblocks" is the one to edit. Tags can contain other tags, and you'll see that used a lot in datapacks in general:
When you want to limit it to ores only, then you need to remove every entry in this list except "vm:ores". This is where you edit the file so that it looks like this:
Then save the file and zip the datapack back up again so that the folderstructure is the same as in the first picture. And that's all there is to it. I hope that helped so that you can customise this datapack even more.