I changed from CalyxOS zu iodéOS four weeks ago. (Motorola G32)
Did not need any adb stuff.
BUT: CalyxOS automatically relocks the bootloader after the installation. Therefore, you will first need to unlock it (again).
If you run Installation - iodé the installer (download, unzip), you will need to activate USB-Debugging. The unlock code is still the same like in the mail obtained from Motorola back when you flashed CalyxOS in the first place. Click on “unlock”, then confirm unlocking the bootloader on your Motorola (by toggling with the volume button and confirming with start button).
You should now see a picture of a little space shuttle and below
“flashing unlocked” on your Motorola. Flashing starts and you should resist to do anything on the smartphone!
(reboot system now or reboot to bootloader - keep your hands off it)
Only when your Motorola asks whether you want to lock the bootloader, you can confirm to lock it. The installation will be complete by this time.
BTW: I did all this on Win 10 pro.