If there's a particular and important chat you access frequently, you can create a shortcut for it on your device's home screen. Here's how:
Long-press on the specific chat in the chat list until it's selected.
Tap on the three dots (top right).
Choose "Add chat shortcut."
Tap on "Add".
This will create a shortcut icon on your device's home screen, so you can save time by accessing the chat directly without opening WhatsApp first.