If you wish you had a faster computer
Here are some tips for those who find some operations slower than they would like:
Work on a smaller section of the score at a time. Break the project up into parts and work on those parts individually until the final layout stage.
Switch on multi-rests as late as possible.
When working in Edit Mode, set Default Bars Across The Staff to a small value, for example 2.
In Edit Mode, resize the window so that only one grand staff at a time is visible.
Consider upgrading your computer hardware.