Kernel Panic loop on iMac and no startup mode works Hello so my iMac (late 2015) has been giving the following on startup:

panic(cpu 0 caller 0xffffff8013b9654e): dessert failed Buildroot/Library/Caches/com.apple.xbs/Sources/CoreStorage/CoreStorage-540.30.1/core/btree/btree_tmpl.h
Debugger called: &lt;panic&gt;
Backtrace (CPU-2), Frame : Return Address
* some bunch of hexadecimal addresses here * 
Kernel Extension in backtrace:
HID: legacy shim 2
HID: legacy shim 2
[HID] [ATC] AppleDevicemanagementHIDEvenetService::processWakeReason
Wake Reason
System uptime in nanoseconds: 141914740


What I have tried


Rebooting with CMD+R - Still in the loop
Rebooting with Option+CMD+R - Still in the loop
Rebooting with Option+CMD+R+P - Managed to connect to WiFi then a loading bar for 10 minutes then back in the loop.
Rebooting with Shift+Option+CMD+R - Still in the loop
Rebooting with Option - I only get the Macintosh option. A bootable USB doesn't even show, even though I tried it on another Mac and it works like a charm.
Rebooting with D - Did the diagnostics, got "No issues found" and I was prompted that my Mac would startup in Recovery. Then I get stuck in the loop again.
Rebooting with N - Flashing world icon and that's it.
Rebooting with CMD+F - Thunderbolt icon and that's it
Rebooting with CMD+V - Vaultmode a bunch of scipt terminal lines, then back in the loop.
Rebooting with Shift - Not useful


I could not seem to access my iMac elsewhere. Any suggestions are appreciated. Thanks.
I would bring a second OS like recovery and erase it or bring this Mac in target disk mode to attempt a data transfer or erase/repair. 


https://support.apple.com/en-us/HT201314
https://www.prosofteng.com/blog/using-target-disk-mode-to-recover-macintosh-hard-drive


It’s possible you have a hardware issue, but why not exhaust some extra steps before you attempt to erase the drive entirely and confirm it’s hardware or you just needed an erase?

When you follow the links above you can consider a data transfer and then do the erase. If no OS including internet recovery works, your kernel panics will be hardware to resolve and not software. 


https://support.apple.com/en-us/HT200553