At "START, Settings, System, Storage, Free up space now", do not delete your Downloads, unless you've got them backed up. It is a permanent delete...
However, if you believe your DirectX Shader Cache is corrupt or too large, you may delete it. The stuff in it is permanently deleted - but the cache will regenerate & fill again. It may take a reboot to get it back, though. I ran DxDiag (ask Cortana) & viewed videos on the WEB - but it did not return until after a reboot.