[Samsung Galaxy Tab A series Guides, News, & Discus] Aramir:
By the way in this tutorial you mention Odin3 v3.14.4.exe but your screenshots are using Odin3 v3.14.1.exe and from what I've read in the comments you should not be using the patched v3.14.4.exe. Also you're linking to a thread wich do not have the odin files anymore. Here's where I got mine (3.14.1) : https://xdaforums.com/t/patched-odin-3-13-1.3762572/

Also I faced the "Only official release binaries are allowed" error like others... So now I'm giving this method a try https://xdaforums.com/t/guide-sm-t5...root-with-magisk.4185993/page-7#post-84721057 in order to skirt the problem. It might be worh an update to the original post too. And it's working ! thanks. For those who have troubles understanding what he meant:

1/ upon startup, click the accessibility thingy, go back.

2/ select your country and language

2/ Do not choose reboot ! back up to the first screen

3/ click the accessibility button, back again to the first screen

4/ now sliding the right should greet you with the licenses screen instead of language selection. Letting you finish the whole process

Also I confirm that even after unlocking the bootloader and patching the boot with magisk the widevine is still L1.

Also I don't understand yet the very final step. "We're not done yet [...] open magisk from the app drawer" . I don't have any magisk app ? I just reformated and flashed the whole thing. Yes the AP part of the firmware is bigger (by about 80MB) but upon booting up I spot no differences whatsoever with the stock rom.

EDIT : And now my magik patched AP FAILS during Odin patching. I swear it passed the first time .... I have no clues about what is going on.

EDIT2 : looks like I was going a little too fast when reflashing stock rom, you do need to login your google account and let it do its things before flashing back the magisk patched one....

EDIT3 : Ok so I was a dumbass and didn't notice the pre installed magisk stub (different icon, I expected it to have the same icon and be on the home screen. My bad)... This time I managed to install everything, restart the device, no "Only official released binaries are allowed" error. BUT magisk fails the safetynet check (whatever it means) for some reasons. Cf attachments. But hey, rootchecker is happy so I'm calling it a day for now.

EDIT4 : toggling MagiskHide on/off enabled BasicIntegrity for Safetynet (still looking for ctsprofile). Also I'm trying to use link2sd to move app and ALL OF ITS DATA (unlike the stock "move to sd option") to the sd card but for some reasons, it refuses to create the mount scripts. Despite havint root privileges it claims for some file to be read-only. And when trying to chmod the permissions throught adb shell, I've got an android popup saying that permission has been denied... Am I not supposed to choose when to agree / deny permissions ? Ow ok I'm a dumb asss again, you are supposed to go in the magisk app, click the little shield at the bottom, and there you can set the permissions. But even using adb shell I can't edit debuggerd's permissions (cf attachment)

EDIT5 : Ok so I've read more about magisk and "modern Android" stuff. It seems like due to how there is a "super.img" partition now we can't (easily) mount /system as +rw therefore link2sd seems pretty much useless nowadays. I'll have to find another way to move the 8GB of genshin on the sd card. As whenever I try to move it to sd card using appmgriii or stock method (appmgriii seems to "just be" an automatisation of the stock method) the 8.8gb application (8gb data + 800mb app) morph into a 800mb app with 0mb data and the 8gb is still sitting in the intern memory. Also still no update on ctsProfile, I've installed MagiskHide Props Config and there's probably some messing around with it I'm supposed to do, but I haven't figured it out yet.

EDIT6 : Ok so Link2sd is dead. Appmgriii is a fraud do not meet my demand. But App2sd (by Vicky Bonick) works just great as for Link2sd it requires splitting the sdcard into two partitions (one fat32 still accessible by the device + one f2fs partition used for linking apps on the SD card). And yes this app just work, it moves everything. So now I can focus back on that safetynet thing. About that, while trying to spoof fingerprints I lost the check on "basicIntegrity" ...