[Verizon Samsung Galaxy S7 Edge Questions & Answers] tacticalone:
I've been screwing around with this for three weeks and I'm unable to make ANY headway no matter how much I search.

I had rooted my s7 edge when I first got it 6 months ago and followed a guide on here which I'm unable to locate. My phone started acting super crazy and losing running apps and apps closing unexpectedly. For example while watching Netflix, the card with the netflix controls in the dropdown would disappear after only a few minutes and netflix would forget it was connected to a chromecast, among other things.

I performed a factory reset. Upon reset and reinstalling my apps I went to try a system update in Settings. Clicking on it immediately results in "Unfortunately Settings has Stopped" and crashing out to the home screen. I recall the root method had some sort of add-on you could flash that disabled/removed many bloatwares and certain "features" and things on the phone including system update.

As I can't find the instructions I used I decided to simply flash the latest firmware using Odin 3.10.7 and 3.11.1 and this method: https://xdaforums.com/verizon-s7-edge/how-to/odin-stock-nougat-firmware-t3570156

Odin checks the files just fine. When the start button is pressed odin sits for 3minutes attempting to set up the connection, then fails out with a red FAIL.

Attempting to install TWRP using heimdall on windows results in:

C:\Users\pl\Desktop\Heimdall Suite>heimdall flash --RECOVERY twrp-3.1.1-0-hero2lte.img --no-reboot --verbose
Heimdall v1.4.0

Copyright (c) 2010-2013, Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Manufacturer: "Sasmsung"
Product: "MSM8996"

length: 18
device class: 2
S/N: 0
VID:PID: 04E8:685D
bcdDevice: 0100
iMan:iProd:iSer: 1:2:0
nb confs: 1

interface[0].altsetting[0]: num endpoints = 1
Class.SubClass.Protocol: 02.02.01
endpoint[0].address: 82
max packet size: 0010
polling interval: 09

interface[1].altsetting[0]: num endpoints = 2
Class.SubClass.Protocol: 0A.00.00
endpoint[0].address: 81
max packet size: 0200
polling interval: 00
endpoint[1].address: 01
max packet size: 0200
polling interval: 00
Claiming interface...
Setting up interface...

Initialising protocol...
WARNING: Control transfer #1 failed. Result: -9
WARNING: Control transfer #2 failed. Result: -9
WARNING: Control transfer #3 failed. Result: -9
WARNING: Control transfer #4 failed. Result: -9
WARNING: Control transfer #5 failed. Result: -9
WARNING: Control transfer #6 failed. Result: -9
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
PIT file download successful.

Uploading RECOVERY
0%
...
100%
RECOVERY upload successful

Ending session...
ERROR: Failed to unpack received packet.
ERROR: Failed to receive session end confirmation!
Releasing device interface...

A similar attempt on linux using Heimdall 1.4.1 results in dozens of warnings throughout