This is what actually happened.
Downloaded deeptest. Did not work for the first time but tried restarting my phone a couple of times, and it just worked.
I followed Arvaaz instruction (The starter of this thread). But the problem is the ”boot.img” and ”vbmeta.img” (I think) is from realme 6 pro or 6i so it did not work properly. Every time my phone rotates from portrait to landscape my phone restarts then looped.
So I tried downloading the ”OTA“ version of my rom. (RMX2001_11_OTA_0450) from some website (I forgot the site). The OTA version is only 3+gb. The full rom sizes from 10 to 13gb Which you cannot save to a fat32 sd file system because of the file system limit of 4gb (even if the size of your SD card is 64gb. (If you change the SD file system to ntfs, you will be able to save huge file size to your SD but the problem is realme6 will not recognize ntfs file system).
I transferred the 3+gb stock OTA rom to new formatted SD and flashed it using the stock recovery. So now I got a new phone using a stock OPPO rom. Because one of oppo's phone uses the same rom.
I extracted the boot.img and vbmeta.img from the stock OTA rom.
I installed magisk manager and patched the extracted boot.img and vbmeta.img.
I downloaded Aarvas' files extracted them and in the same folder I put and overwritten the boot.img and vbmeta.img with the ones that I patched.
In my phone I checked the USB debugging. (my bootloader is already unlocked by deeptest) and connected it to my PC.
Then ran the command from the folder which I extracted Arvaaz files, fastboot, and my own patched imgs.
In the ADB console, I typed "adb reboot bootloader" to reboot my phone into fastboot mode.
And then I typed "fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img"
Then I typed "fastboot flash boot boot.img"
Rebooted my phone when it finished
Installed magisk manager
Installed magisk
Rebooted my phone
I ate because I'm hungry
Took a bath and then made coffee
I sat down and took my phone and BOOM....I forgot my coffee was hot.
Then looked and my phone was rooted without any problem like the one I encountered before and finished my coffee and still am using with full administrator privileges.
Note that every command input in adb has no ” symbol.
I'm in the Philippines and I used East Asian OTA rom.
I hope that this helped.