How to set PowerShell 7 as default and remove other versions

To make PowerShell 7 the default shell for Windows Terminal, follow these steps:

1. Click on the down arrow and press settings
2. A json file will open, and you will see a line near the top that has a parameter called defaultProfile with a UUID.
3. Also you will see a line representing the UUID of the PowerShell 7.0
4. Copy that UUID and put it in for defaultProfile

Good Luck!

Source:

Defaulting Windows Terminal to PowerShell 7.x Core