Sets Serialize\StartupDelayInMSec = 0 so your startup programs launch immediately at sign-in instead of after Windows' built-in ~10-second stagger. Snappier login if you trust your startup list (use the Startup manager to trim it first). Reversible.
MaxTweaks applies this tweak with one click and snapshots your original setting first, so you can revert it cleanly at any time. A System Restore point is offered before batch changes, and every tweak links to its official source.
Get MaxTweaksOfficial documentation: https://learn.microsoft.com/en-us/windows/win32/shell/