How to embed a custom calculator tool without breaking theme updates?

Hi CatchThemes Support & Community,   I’m using one of your themes (great work, by the way) and recently built a small web calculator tool (for something like UAE end-of-service benefits). I want to embed it into my WordPress site so that users can calculate without leaving the site.   My challenge: whenever I update the theme, custom code I add sometimes gets overwritten or causes conflict.   Some of my thoughts and questions:   Is it better to package this calculator as a small plugin, rather than inserting directly into theme files?   What hooks or enqueue methods recommended in CatchThemes are safe for custom scripts/styles?   How can I isolate custom templates or blocks so that theme updates don’t corrupt them?   Should I use shortcode or a custom block for embedding the UI? Which is safer long-term?     If anyone has experience embedding utility tools inside CatchThemes — especially keeping them update-proof — I’d love to see how you structured it. Thanks in advance!