Netgear MR6500 - Will NOT boot past "NETGEAR" logo screen

[KLLC]

I have a Netgear MR6500.  Purchased outright from Best Buy, and SIM unlocked by ATT, all happening over 1 year ago (so I believe it is out of warranty?).

I was using it as hotspot with ATT. Was getting sluggishness and slow-downs in the UI during first week of August, so I removed the SIM card, and I physically factory reset the device (pushed paperclip end into "reset" hole; held for 10 seconds to allow to reboot). When device rebooted, the "NETGEAR" logo screen came on, and stayed on.  After 22 minutes of no change from the "NETGEAR" logo screen, I again physically factory reset the device; same result. 

Now, when I plug in or turn on device, device cannot get past the "NETGEAR" logo screen; sometimes, after 5-8 minutes, the "NETGEAR" logo screen turns off.  I believe that the firmware for my device got updated (without my consent) and/or corrupted (i.e., as has been reported with that lousy firmware update that got pushed to devices in Q2 2023).

I understand that there is now an updated firmware that fixes that lousy Q2 2023 firmware update (see, e.g., https://community.netgear.com/t5/Cell-Service-Mobile-Hotspot/Nighthawk-m6-pro-MR-6500-keeps-restarti...).  But, I have no ability to install that updated firmware due to the state of my device.

If I could access my device's GUI, I could initiate a firmware update (per the steps found at the above link).  But, since my device cannot get past the "NETGEAR" logo screen, I cannot access the device GUI.

I can access the firmware downloader screen (i.e., plug in device while holding device power button and battery being out; I get the "Downloading Software" screen).  So, if I had a downloaded version of the firmware (i.e., .spk file), whether the initial firmware from the factory or the latest firmware found at the above link, and an appropriate firmware flashing tool (e.g., fdt.exe), I could re-flash my device from the firmware downloader screen. But, since I do not have, and do not know where to get, the downloaded version of the firmware (even the initial firmware from the factory would be fine, as I could allow updates to happen OTA) or the flashing tool, I cannot restore my device.

I am looking for assistance on how to get my device working again, whether via the above means or some other means about which I have not yet thought.  I would prefer the initial firmware from the factory (and allow update OTAs to proceed in due course), but I will settle for any firmware version that makes my device operational again. Any assistance appreciated.

Thanks in advance.