Shopify App Extension block does not work with cart drawer

Hi, I’ve created a Shopify App currently in development and successfully created an app extension block that can be added to the cart page. I realized that there is also a cart drawer which doesn’t seem to be configured by the cart page. There’s no customization page for me to add the block there (afaik).

How can I get the cart drawer to always accurately display a snippet like this:

<div>
  This is the cart price doubled: {{ cart.checkout_charge_amount | times: 2 | money_with_currency }}
</div>

I’m exploring making an embedded app but I’m not sure how to hook into a cart being updated and adding a div into the cart drawer with something like the snippet.

Any guidance would be appreciated, thanks.

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Also need help here!