Well you're not in the correct directory then, or your update file is called something else.
For me have to write .\adb sideload Update.zipWell you're not in the correct directory then, or your update file is called something else.
1. Open command prompt/powershell.
2. Make sure your phone is in sideload mode and type adb devices to make sure it shows up in adb.
2. cd to the correct directory where you stored the update file. For example: cd C:\Users\blabla\Downloads
3. Then run adb sideload .\filename.zip. Replace filename.zip with whatever the name of your update file is of course.
I had found this:
Lets see, latest OTA update, which for me is android 12, with one ui version 4.1