Is there a way to add "Show All" to the list of Visible Rows

I have 3 more clarifying questions. Thanks for your patience. I think it is a needed education for me though to understand how I may hurt my project in the future. 1. If my filter is set to Always On, is that what drives what is pulled/retrieved the first time the page loads. I.E. Let’s say I have 1 million records. I have a filter that is set to “always on” that would limit the total records to 500. Does that first retrieval pull 1 million records in or does it look at the filter which is always on and then pull in the 500 records according to the filter? 2. Same use case we have 1 million records but the User Profile only has security access to 100 of the 1 million records. Does the model pull in 1 million or does it pull in 100 according to the users security model? I know it will only show them the 100 based on security but do we risk breaking the page if the number is set too high. 3. We are using the Calendar to create a master calendar where the view is controlled by Salesforce sharing rules (i.e. What geographic area they are assigned to). I do want to show all calendar events (or at least those in the recent past and into the future). Is there a point when I risk breaking the calendar page if I have too many records. Is there best practices for these use cases. Thanks for your help, I am trying to future proof my nuild to elimiate surprises.