Immediately post iOS 18.4 upgrade yesterday 2023 MacBook Pro 14″ battery level dropped to zero and indicates "Service Recommended". System report shows battery charge cycles at "0". Wondering if others have seen this occurance on other laptops?
iOS 18.4 update creates laptop battery issue
Can you try Apple Diagnostic, Safe Mode and reinstall MacOS ?
https://support.apple.com/en-my/102550
https://support.apple.com/en-my/guide/mac-help/mh21245/mac
https://support.apple.com/en-us/102605?displayMode
https://support.apple.com/guide/mac-help/reinstall-macos-mchlp1599/mac (without data delete)