I don't know about safetynet since I've installed xposed and don't use any apps that requires me to not to have any root access or other framework type things in my system. But I can confirm that without systemless xposed enabled in magisk I'm too passing safetynet, having a working viper. Also my selinux is restricted now and it all works.
---------- Post added at 07:17 AM ---------- Previous post was at 07:11 AM ----------
8.4.26 but works with other firmwares too (8.3.29 onwards). Rest is same with my comment above . Plus, I'm always installing as first wipe everything, then format userdata, then fw+rom+gapps+some basic additions (as custom font etc so can be flashed at any time, don't care simply), then reboot, configure everything. After all restore things and so, back to twrp and flash magisk, magisk modules. All working this way.