Braintree Plugin not installed

it seems that I can’t use Braintree Ionic plugin with Capacitor because it will not installed when I sync plugins with ionic cap sync command.

Are there any solutions?

looks like you should be using a fork of the original one linked above. Based on what I saw, this fork looks like it is compatible with Capacitor - GitHub - redarea-snc/cordova-plugin-braintree: A Cordova plugin for the Braintree mobile payment processing SDK.