Win11 Laptop battery drain occurs in sleep mode even when Modern Standby is disabled

You have already changed sleep settings and disabled wake timers, yet the battery still falls quickly, especially with USB hardware attached. First run powercfg /a in an elevated Command Prompt; this confirms the sleep model Windows is actually using, rather than relying on a registry or BIOS label. If Modern Standby is listed, generate powercfg /sleepstudy /duration 3. Otherwise generate powercfg /systemsleepdiagnostics and powercfg /systempowerreport. Compare one overnight test with every USB device disconnected against another with the usual device attached. Also run powercfg /devicequery wake_armed and powercfg /lastwake. Update Windows, BIOS, chipset, USB, and graphics drivers from the device manufacturer. Disable wake capability only for a device identified by the reports, not every device. If the laptop still drains in a confirmed sleep state, use Hibernate for unattended periods and give the reports to the manufacturer; persistent drain can be firmware, device-driver, or battery related.