Hi,
Something here might help:
Editing Windows Terminal JSON Settings
https://github.com/microsoft/terminal/blob/master/doc/user-docs/UsingJsonSettings.md
You may change the default applications by file type by going to the Settings > Default apps > scroll down and go to "Choose default applications by file type" > look for .json and you may change it there by clicking the + Choose a default.
Best regards,
Leon