Tawk.to conversion tracking in GA4

Hi, we have Tawk.to live chat set up on our website and we want to track conversions in GA4 using Google Tag Manager. Tawk.to, GA4 and GTM accounts are all set up. We just need help creating the correct GTM tag that sends the event into GA4 so we can mark it as a conversion.

Users need to fill in the Tawk.to form before they can chat, so the form submission would be the event we want to track.

We had this working in the old version of Google Analytics (UA), but we can't figure out how to get it working for GA4. Screenshot attached.