Hmmm … I don’t use the /e/ recovery, and I don’t have your device.
ADB Sideload needs to be started in the recovery first. I guess there should be some message on the phone that Sideload was started or that the phone would wait for file transfer now or something like this.
Then adb devices on the computer should report the serial number along with “sideload” to confirm the recovery really is in ADB Sideload mode.
Then execute the adb sideload command.
As said … TWRP’s Install does the same job, but it needs the ZIP file somewhere on the phone, either in Internal Storage or on an external SD card.