Answers for "root composer.json requires php ^7.3 but your php version (8.1.4) does not satisfy that requirement"

Root composer.json requires php ^7.2.5 but your php version (8.0.6) does not satisfy that requirement.

composer install --ignore-platform-reqs

Root composer.json requires php ^7.2.5 but your php version (8.0.3) does not satisfy that require

It's becouse in your project in composer.json file you have:

"require": {
    "php": ">=7.3",
    .....
},
Try to update this requirement to:

"require": {
    "php": "^7.3|^8.0",
    .....
},

root composer.json requires php ^7.1.3 but your php version (8.0.3) does not satisfy that requirement.

On Mac using Home Brew, you can switch php versions easily:
brew unlink [email protected]
brew link [email protected]

Or follow the upgrade path to get your app to support the newer php version