did the flashing via fastboot with the -w option do anything different?
In my case, flashing the ota image via adb worked fine. My system was running nicely again afterwards. Apparently you also managed to flash the new system but something different must be changed. Can you install any apps at all? I would be interested, in seeing your partitioning of the internal memory. I’m not a specialist on this, but I have an app called flashfire which lets me see the partition table and make backups of the individual partitions. Maybe you could download it and check what your partition table look like? Download is here: http://flashfireapk.com/FlashFire-Download.html
I’m attaching my FP2 partition table:
I can make individual backups of each, so if we can identify which one has a problem i might just send you a backup that you can flash back to your phone…