Establish the exact Mac and symptom
Use About This Mac or System Information to confirm that the notebook has Apple silicon, then record the macOS version, battery percentage before and after sleep, sleep duration, and attached accessories. Compare at least several ordinary sessions before calling a change a regression. Include whether the Mac was warm or clearly woke during the interval.
A battery percentage is an outcome, not a diagnosis. Battery condition, a busy process before sleep, a connected dock, and repeated wakes can lead to superficially similar results. Keeping the conditions comparable makes later evidence much easier to interpret.
Check software and peripherals
Before sleep, use Activity Monitor's Energy pane to look for apps preventing sleep or showing unusual activity. Then perform one controlled sleep with nonessential displays, hubs, storage, and input devices removed. Do not change several settings at the same time. If the result improves, add one variable back for a later comparison.
WattGuard can organize macOS sleep and wake history with battery-change observations. It can expose timing and recurring clues, but wake reasons do not prove which item caused all drain. Use the history to choose the smallest next test.
Use Apple-silicon-appropriate recovery steps
Apple's SMC reset instructions are for Intel-based Macs. Apple says an SMC reset is not needed on a Mac with Apple silicon, so presenting it as a repair for this model is inaccurate. If a controlled pattern persists, restart normally, keep macOS current, and use Apple Diagnostics when hardware is a concern.
Avoid a universal hibernation setting change. It can alter expected sleep behavior and may hide the original pattern without explaining it. Keep the baseline, one change, and recheck approach so a service conversation has useful facts.
Escalate with useful evidence
For persistent reproducible drain, share the Mac model, macOS version, battery condition, connected equipment, and comparable-session notes with Apple Support. If Apple Diagnostics produces a reference code, retain it. This makes the investigation more precise than an unsupported claim that the silicon generation itself is defective.