Does anyone know if it is possible to flash the Magisk zip directly from the /e/ recovery to reroot the phone after an update? Because the only option that seems to be available in the settings is to do it via adb sideload from a computer. I know it can be done from TWRP for example, but apparently there is no official version available for the oneplus nord avicii, and I would prefer to keep the “official” recovery if possible.
Thanks in advance for your advice.
Are you talking about a one-off scenario, where you updated your phone and it is not rooted after reboot, or generaly about preserving root after OTA?
For the earlier, I believe you have to use adb to re-root your phone, if you use /e/recovery
But if you have an A/B partition phone (which I believe avicii is), then you can patch the partition after update, before you reboot. Look for “Install → Install to inactive slot” in the app after an update.
Just saying, but rooting is not encouraged by /e/, so choose wisely if you really need it.
Thanks for the answer. Yes, that’s what I noticed, you have to go through adb sideload to reflash magisk after each update. Previously, TWRP, which has the function to flash a file directly from the phone, was available for my old Oneplus 3T. But it is not yet officially supported for avicii. So I’ll have to make do with that.
Thanks also for the warning about the root. I’ve been doing it for a long time knowingly. For adaway, oandbackupx among others, which are quite indispensable to me. 
Sorry, but maybe I was not clear in my previous post. I think you dont need the ADB sideload method after each OTA, since I think avicii is A/B partition phone (i.e. supporting seamless updates = your phone downloads and also installs the OTA while turned on, then you are asked to simply reboot the device, right? There are also tools to see if you have an A/B partition phone). If that is true, then after the OTA install is finished, but before you reboot, you can open Magisk app and select Install → Install to inactive slot. Then after reboot, you should have the OTA and still maintain root.
Okay, it’s actually clearer that way. I understand the trick better. Thanks for having solved that. 