While Adobe Photoshop 2021 installers are still available through official channels for specific use cases, downloading files from third-party sources labeled "TNT" or "TNTdmg" is strongly discouraged due to significant security risks and legal issues. The Risks of "TNT" and Third-Party Downloads

Regarding the "free mode install" part of your request, I must emphasize that Adobe Photoshop 2021 is a paid software. However, Adobe does offer a free trial version of Photoshop 2021, which can be used for a limited time.