Bypassing or removing a password is one thing, and also often not really possible for most encrypted devices with UFI with some exceptions. Let's agree that systemui methods or something similar is not a valid solution. Oppo solution is some other exploit, where they don't touch userdata partiton either. Decrypting data outside the phone is something else entirely, and the main problem is that key partially depends on the hardware. Sorry to say that, but that's the reality nowadays, even for forensics type software.
You can't browse it because UFI doesn't detect the filesystem, either because it is encrypted or unknown for UFI - like F2FS i mentioned before. Dump it and check the header with some hex editor to be sure. My guess is, that it's the encryption.
As for scatter, you don't really need it. Dump userdata partition into a single file, then you can read (identify) a new phone by USB (you may need a firmware file or a correct DA file) and you'll see all the partitions. You can then load your dumped userdata and flash it directly. Keep in mind that it won't be much of a help, and most likely you'll see an encryption error while the phone will boot. That's why i said you need to transplant both CPU and eMMC.