I avoid this slowdown by mapping every single app I use to a two key binding.

https://github.com/nikitavoloboev/dotfiles/blob/master/karab...

i.e. w+l opens VS Code. w+k opens Safari and so on. It's instant, no lag at all.

I also bind four finger swipes to open top apps with BetterTouchTool.

i.e. four finger swipe up opens Safari, swipe right = VS Code, swipe left = iTerm.