When I’ve flashed root before this, the cache had to be wiped and I’m pretty sure that gets populated when u do a boot into the OS. So to get around starting to get the cache filled, just flash Magisk before the first boot. If u already have it setup and don’t wanna re-install then just boot into recovery and wipe the cache or do a factory reset.
Here is Magisk I used (I downloaded it on this board on another post) and don’t know if it’s /e/ specific but it worked for me:
https://ecloud.global/s/KAQwPmPJ2bNTM4c
That TWRP was off the install page for /e/ on Sony Xperia XA2 and is just for our phone.
Marty