Otherwise, let's look into different app options. First, I would recommend checking the PageFly Landing Page Builder app. This means you can create your custom product page compatible with bundle apps.
Then I'll share the Bundles Upsell app with you as it's fully customizable to fit your brand. So, maybe you can achieve the same look with their editor.
Finally, your theme may have a button variants option already built-in. Let me know what theme you use, and I can check for you.
I hope this helps. Let me know what you think.
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