So can it run on win7 dx11?

If you can’t/wont run Windows 10, all I can suggest is getting a console that D2:R plays on. Blizzard is not going to support the game running on a 12 year old unsupported operating system.

If you’re having trouble upgrading from 7 to 10, the next step is a clean installation of Windows 10. Create a bootable USB installer for Windows 10 and boot from it. Don’t forget to back up your data beforehand.

D2R runs on DX12 (at least by default), doubt they will add DX11 RHI before the release if they didn’t so far, bugs are more important than supporting mostly obsolete platform (W7) and changing requirements just before release.

If you type /fps or /framerate it will show your FPS, it also shows that it’s running DX12.