Update from RingCentral (edited original description):
We've received interest from customers who use HighLevel, an all-in-one marketing and CRM platform designed for agencies and small businesses, requesting a native integration with RingCentral via the App Connect framework. HighLevel brings together tools for lead generation, SMS and email marketing, sales pipeline management, and client communication. A RingCentral integration could enable automations such as logging calls into HighLevel contact records, triggering campaigns based on call outcomes, or sending automated follow-ups after missed calls—all within the existing workflows HighLevel users rely on.

If you're a HighLevel customer and see value in this integration, we invite you to vote for this idea to help us prioritize it.