Is there an endpoint that offers metrics for a Landing Page, specifically the Submissions and Submissions Rate?
Yes, really looking for these metrics. But looks like they don’t exist in the API as per this thread - Reproducing dashboard via API
There isn’t currently a public API for analytics data like landing page submissions. You can get submission information related to particular contact records from the Contacts API, however. If you have the inclination, I would encourage you to check out the Ideas Forum on the HubSpot Community. There, you can create a post including your use case that product and other customers can see.