I don't know why, but i still getting same error when i try to grant root access to voip recorder even with magisk version 21.4, as for this guy from yt worked with that version of magisk (you can clearly see version on 2:48):
i wasn't wiping phone or hard reseting it (i want to try avoid that whole process if possible, but i have full backup of phone on pc just in case), but was doing full uninstall option from magisk app itself, then was through usb and command window on pc rebooting bootloader and flashing twrp recovery again, in which was entering later on to flash zip file of magisk 21.4, but still no use. I don't know if it doesn't work because i need to try even more old versions of magisk, or because i'm forced to wiping out whole phone if something remained in system that indicates other apps on new version of magisk even if i fully uninstalled it and flashed old ones through twrp. It would be useful if someone knows what is last version of magisk that voip recorder support, or any other solution to this(android 8 lg h930ds)
Update: i FINALLY managed to make app actually works, i was using this site, downloading all versions of xapk through lucky patcher, and found out that latest version that works with my device is 1.7 (all tried on magisk 20.4, but now i realising that maybe isn't about magisk version, but actually about app version, for some reason 1.7 works while newer versions of app doesn't), now will trying same version of app on newer versions of magisk, this is site: https://apkpure.com/voip-recorder-screen-recorder/com.boldbeast.voiprecorder/versions
2nd update: it's about BOTH magisk version and app version, i tried all combinations of versions of both, and discovered that latest versions combo that makes app work on my device are magisk v20.4 and voip recorder v1.7, i will try using that older version of magisk for a while and see if anything will miss compared to later versions(except design as i see that literally right next version of magisk is todays look, while my version is last one with older look with black and sliding menu, but i don't mind that at all, i have to see if magisk hide works), maybe for every device is different combo of versions of app and magisk? You should all try more combinations in order to make it works.