Good evening Geoff and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the struggles you have been experiencing with the license key.
I would love to help you with this topic.
However, before that, I am noticing that you are still using Event Rocket.
Although it was a great plugin, this plugin is known to break things since version 4x+ of the Events Calendar plugins.
And since most of its features are now built-in our other plugins, I would strongly recommend deactivating it.
With that in mind, I would try completely removing your license key, disconnecting it and reinstating it. Here is a helpful knowledge base article on that subject: https://theeventscalendar.com/knowledgebase/moving-your-license-keys/
If that does not work out, I would recommend completely deactivating and deleting the Events Calendar Pro plugin and then going to https://theeventscalendar.com/my-account/downloads/ to grab the latest version and install it using WP’s built-in Add New plugin interface (via the .zip file).
Let me know how that goes.
Best regards,
Geoff B.