On the device, select “Apply Update”, then “Apply from ADB” to begin sideload.I successfully flashed recovery but when I try to flash LineageOS I get the "device offline" error. adb devices shows no devices attached. Fastboot works and I can flash both recovery builds on the Lineage website, but again can't flash Lineage from ADB inside recovery.
adb.exe sideload lineage-18.1-20210930-nightly-barbet-signed.zip
adb: sideload connection failed: device offline
adb: trying pre-KitKat sideload method...
adb: pre-KitKat sideload connection failed: device offline
List of devices attached