Our app already allow you to stack discounts on top of our Bundler discounts.

But, you have to allow that inside Shopify admin.

To do so, go to: Shopify admin > Discounts > Open a discount code or automatic discount you'd like to edit > Combinations.

At this stage, enable product and order discounts.

As for subscription discount stacking, you'd need to do that in Bundler.

To do so, go to: Bundler > Open the bundle you'd like to edit > Bundle settings > Enable "apply on subscriptions".