Enabling Automatically hide and show the dock in System Settings > Desktop & Dock is a way to great way to gain more screen space.

The default delay when the dock appears, however, can hinder productivity.

Fortunately, It’s possible to reduce or even completely eliminate this animation delay.

How?

1. First, Open the Terminal app.
2. Enter one of the commands below.

To fully disable the delay:

defaults write com.apple.dock autohide-time-modifier -int 0; killall Dock

To minimize the delay (to 0.10s):

defaults write com.apple.dock autohide-time-modifier -float 0.10; killall Dock

You can also customize the delay by changing the number 0.10 to your desired value.

To Restore the Default Settings

defaults delete com.apple.dock autohide-time-modifier; killall Dock

Reference

https://apple.stackexchange.com/questions/33600/how-can-i-make-auto-hide-show-for-the-dock-faster: How to quickly open the hidden Dock on macOS