You are running your own licensed OS and Office on foreign hardware. This is 100% legal, completely secure, and offers better performance than any cracked "portable" tool. The downside? It requires a $300 investment and a 128GB+ SSD.
. Using older versions, especially unofficial portable ones, increases exposure to security vulnerabilities as they no longer receive security updates. Microsoft Support for mobile productivity, such as Microsoft 365 Web Office on mobile microsoft office 2019 portable top