Aggregate function slowing down my file

A few weeks back I learned about the "=AGGREGATE()" function and been using it ever since. It works as it should, but I noticed that since this function was added to my file, the time it takes to open / Update the file has increased heavily.

Any ideas why?
Is there another way to get the result I need (extract the MAX() number from a range while ignoring the errors) without the AGGREGATE function?

Regards,