Hello @jake111,
As you point out, it takes more time to show the global variables when you have lots of them. This is a normal behavior as MCUXpresso IDE User Guide mentions "The usefulness of Live Variables reduces as the number of Globals monitored increases".
Also, it mentions: "Global and Static variables are stored within system RAM memory and can therefore be accessed by the debug chain (read and potentially written) while an application is both paused and running." So, it might be useful to do a code optimization: Tutorial: How to Optimize Code and RAM Size | MCU on Eclipse.
Other suggestions could be closing other projects or views that you may have open and that you are not going to use before debugging (this is because the views could need data from the target which can slow down things), or to open a new workspace.
Is it necessary that every time I open "Global Variables" view, it loads all the global variables?
You could select which variables you want to load checking the boxes of the variables you need and clicking OK. To simplify the selection, you could use type to filter to search for the variables you want to select.


[MCUXpresso IDE User Guide. Figure 12.33. Add Global Variables and Figure 12.34. Global Variable Selector]
Best regards, Raul.