Photoshop version 2020 should work on Window 7 Version 2021 requires Windows 10. Microsoft stopped supporting Windows 7. Is it safe to connect Windows 7 to the Internet? I would not think that it is safe and you have to connect to install Creative cloud Applications.
Applicable for October 2020 release (version 22.0)
Minimum and recommended system requirements for Photoshop
Intel® or AMD processor with 64-bit support; 2 GHz or faster processor with SSE 4.2 or later
Support for Windows 7 has ended for individuals. Enterprise is still supported though under an ESU contract and does receive updates. I'm unsure about compatibility of the installer though. And Windows 10 is great 🙂