So you are using a function node which runs code on the server.
But you don't need to make the server do a load of work when only a person needs to see the output.
Because the Admin UI is not meant to be used as a dashboard, there are several nodes that let you build an end-user interface and presents that as web pages to a users client browser. The easiest one to start with is called simply "Dashboard". It has a node called "Dashboard Template" that lets you create custom code including script.
So rather than trying to handle everything in function nodes - which results in you having lots of data to pass round (1 msg per second per timer), by only passing the data I mention, you can do the calculations and display purely in the users browser.
In your case, when you have a dashboard in Processing, as long as you can get Node-RED to pass data to your Processing dashboard, the principles would be the same, you would be sending a minimal amount of data through to Processing which would then be used in a suitable timer to display the information.