There are several ways in which you can speed up DataTables.
Tip #1 Enable Paging
Tip #2 Disable OrderClasses
Tip #3 Enable DeferRender
Tip #4 Enaber ServerSide
Tip #5 Lighten the load on your query!
Instead of getting all the columns and relationships on your query which can lead to a long time of loading, simplify your query by getting only the necessary columns and data you need before passing it on the client-side.
Reference: DataTables Frequently Asked Questions
