You posted download links to 4pda forum, do you realize 99% of the people will not be able to download it or register. (cyrylic captcha)
Here you have AFH mirrors:
Normal version - TWRP_3.2.1-5_mido.img
Treble version - TWRP_3.2.1-5.mido-treble.i...
There is new version of very solid CameraRN4X_08 gcam tuned for RN4X by Logantrah.
After some testing it's very impressive, among some other new stuff it has bitrate selection for video recording (which seems to be working aswell) it's also super ...
We need the basic stuff fixed first before "performance improvements". Bluetooth calls and fingerprint reader, come on!!
It's open source so feel free to fix it. If you can't then shut up and let the smarter people work and fix whatever they want...
Ok so updated flashing instructions:
1) Use TWRP from OP
2) Wipe System/Vendor/Data/Dalvik&Cache (Format Data & restart recovery if you are encrypted)
3) Flash ROM
4) Flash OpenGapps (ARM64 / Android 9.0)
5) Flash Magisk v16.7 (Optional)