The better comparison is probably Falcon 9 and Crew Dragon in terms of mass / mission etc. Starship is in a totally different class

For Falcon 9 - it will look slower on takeoff as well. One reason not mentioned yet is that after engine start, Falcon is held down until all vehicle systems are verified as functioning normally before release for liftoff. So they can do pressure / thrust etc checks on the ground before releasing.

With solid rocket motors especially - once you light those you are pretty committed.