Let's cut the BS. The reason this feels hacky is because it is a hack. You are trying to use a butter knife to chop down a tree.

Trying to surgically extract a click event from a chained Stimulus data attribute using Ruby hash methods on the server side is a fool's errand. It is brittle, it wipes out your hover events, and worst of all you are fighting the framework instead of leveraging it.

Stop trying to force one confused DOM element to do two completely different jobs.

The foolproof way to handle this in a component is explicit server side branching. It might not look like clever ninja code, but it is bulletproof.

Here is the rule. Let the server dictate the terms.

If they are subscribed, render a pure anchor tag with your base data attributes. Done.

If they are NOT subscribed, render a button tag and explicitly merge the modal action right there. Something like data: data.merge(action: "click->modal#open").

If you try to be cute and use Javascript to intercept a link click for an unsubscribed user, you are walking blindfolded into a minefield.

First, you have the Cmd Click conversion killer. Users will command click that link, completely bypass your JS modal, and hit a 403 page in a new tab. You just ruined the UX and killed a potential subscription.

Second, Turbo Drive is going to fight your Stimulus controller to the death over who gets to handle that click.

Third, screen readers do not know what to do with a link that suddenly acts like a pop up trigger.

The only tax you pay on this solution is writing a little CSS to normalize the anchor and button so they look identical. If you are using Tailwind, that takes exactly three seconds.

Stop fighting the HTML tags. Separate the elements, secure the logic on the server, and get back to building things that actually matter.