I don't think Konsole is actually faster than Kitty or Alacritty. Kitty is really nice and an innovator in a lot of terminal standards. It's also non-commercial and not related to any sort of startup (not that Konsole is either). It's definitely my first choice of the bunch, followed by Alacritty.

Konsole seems to keep up with modern features as well. For instance I realized yesterday that it renders the newer progress codes that clis can emit. I am content.