If you are trying to install a "portable" version over an official one, you must uninstall the original first (though we recommend staying with the official version). Conclusion
Officially, keys are often bought via regional payment platforms (common in China) or through authorized Telegram groups and resellers. License Management:
Regarding your query for a "portable" or "recharge" solution: Official VIP Activation : VIP status is tied to an MT Manager account mt manager vip key recharge portable
Improved performance for multi-threaded transfers when using FTP or SFTP. How to Recharge Your VIP Key