I really hate just writing this but:
There are people that have written guides for all that you ask for. Please use the forum as intended, this questions have been asked alot of times, in your previous thread I also gave you answers if you don't like em say so there instead of making a new thread.
I'll do this one more time....
Fastboot blu_spark twrp 985v2. Img
While in twrp flash blu_spark twrp 985v2.zip
REBOOT to twrp
Flash the full rom.zip
Flash blu_spark twrp 985v2.zip again
REBOOT to twrp
Flash magisk 17.2
Reboot to system
This is the way I did it from beta 3 to stable..... Worked 100%
From 4 to stable should be the same way..
https://forum.xda-developers.com/devdb/project/?id=27466#downloads link to download of twrp img and zip