How to build a prompt system, with each prompt triggered differently?

I have a large web app that sometimes requires user prompting after a release of some feature.

For example, say a feature is released that allows users to now search from a newer dataset. The new dataset is different enough from the old one that an automatic switch-over might be a bit jarring for a user. Instead of opting the user in to the new feature automatically, I would like to prompt them (via a modal with information about the feature) to choose whether they would like to make the switch to the new feature.

I already have flags for the features, and we manually handle individual users through an administration system.

I have hardcoded prompts like this before, but I'm realizing that it is becoming necessary with more frequency.

Each prompt would use a different trigger e.g., button click, form submit, landing on a page, etc.

From a design perspective, what are my options here? How should I store the triggers? As an action may be more complex than toggling a flag, how do I store the action to be taken on the server upon such a trigger?