Google-sheets – Google Sheets IMPORTHTML has long loading time – How to improve efficiency

I'm putting together a spreadsheet of sports statistics that I intend to display certain calculations from on my website once both my site and the spreadsheet are complete.

I currently have 30+ pages in my Google Sheets, each with 3-4 importHTML statements. It takes quite a long time for the entire spreadsheet with all of its pages to finish loading up as it is, and I'm hoping to improve the loading time and, therefore, its efficiency.

Each page is loading from a specific URL. The URL used on each page is unique from the other pages' URLs. The reason there are 3-4 importHTML statements on each page is that I'm loading specific tables, rather than ALL the data from the URL I'm pulling from.

How can I improve efficiency? Is there a better way to do this than 120 individual importHTML statements spread across 30 pages, or am I just going to have to deal with it being very slow if I want to do what I'm doing?

And, as a follow-up question, I also need these importHTML statements to automatically update at certain time intervals. How can I make this happen without having to manually go into each sheet and retype (or copy/paste) the formulas?