anyone know how to track an internal CTA link click in GA4?

You should have some event that triggers when you click on the internal CTA (you can use an analytics debugger chrome extension for this). An example of an event could be "click". Then you have to look after the event_params.key that includes the information you want and setup a query that matches it. The easiest way to go about it is just to use ChatGPT imo.

Make a only link clicks trigger in Google Tag Manager where click URL contains your domain name. Connect this to a GA4 event tag. Include click URL (and click text) as parameters for the event. That should do the trick.

That's what it sounded like I had to do - go through GTM

Good to hear!