It’s hard to find because the hook name is generated dynamically.
All the get_ functions in the WooCommerce product class, like $product->get_price(), use the get_prop() method under the hood. This is part of the WC_Data class that WC_Product extends. At the end of get_prop() the filters are applied like this:
apply_filters( $this->get_hook_prefix() . $key, $value, $this );
And get_hook_prefix() looks like this:
protected function get_hook_prefix() {
return 'woocommerce_' . $this->object_type . '_get_';
}
So all the get_ methods like get_price(), get_sku(), get_description() etc. will go through a filter with the same format: woocommerce_product_get_{property}. In your case woocommerce_product_get_price.
For the new filter, the 2 arguments are the value, $value, and the product, $this. So it doesn’t look like you need to change the callback. It should be sufficient to change the hook name.