Working articles I have been following:

How to use the Emergency Mode to recovery the firmware for Omada Gateways? | TP-Link Canada

ER7206 bricked after firmware upgrade failed? - Business Community (tp-link.com)

The firmware v1.2.0 has been released for ER605 & ER7206 on February 11, 2022 - Business Community (tp-link.com)

ER605 ER7206 v1.2.0 Firmware Release - Business Community (tp-link.com)

  @KillerMBunny 

Did you check your current firmware? Any luck you can recall the current firmware? The firmware recovery mode was added in the v1_1.1.1 build. Meaning you can only recover while your current firmware is 1.1.1 

OK. I met someone who had the same issue before. He resolved this issue by powering off it for a day or two. Just keep it shut down and off the power. 

BTW, how do you upgrade the ER7206? Via the standalone, into the web UI? Or through the Controller?

You may provide the log if you use the Controller. @Fae  or @Hank21  could investigate it for you. 

  @John1234 

Been a hell of a week... just wishing I could reach SMB support... I was able to talk to Abdel here in Canada... but seems to be a nightmare finding someone local.  As for your questions John....

Did you check your current firmware? Any luck you can recall the current firmware? ( I did when I was looking for the freshest versions, as I was already aware of Log4J and few other concerns... but being a dumb ass, I did not make note of where I was starting from...)

The firmware recovery mode was added in the v1_1.1.1 build. Meaning you can only recover while your current firmware is 1.1.1 (where were you a week ago? LOL... wish I knew that sooner, I would have made that a transitional hop..)

OK. I met someone who had the same issue before. He resolved this issue by powering off it for a day or two. Just keep it shut down and off the power. ( Nah, sad to say this was dead on the vine.... the update clearly went foul...)

BTW, how do you upgrade the ER7206? Via the standalone, into the web UI? Or through the Controller?

So what happened was I ended up sending back to Amazon as DOA, per supports recommendadtion as they believe it failed hard. I also had a talk with Canadian suppport, and was able to get advice. They too didn't think I did anything wrong , just dumb luck. ( Thanks Abdel for your help and time) I have flashed firmware on thousands of devices in my time and while on occasion things dont alwasy go well , I have never been unable to recover. this is my first brick in over 30 years. 

The new one came Wednesday, I incrementally updated it as standalone. to 1.1.1 then to 1.2.0  ( Worked fine...) 

then my Switch (TL-SG2008P) , and then the OC200.

I have 2 N300 outdoor AP's and all the core parts tied into my cloud now... but have to get some advice on that front... Past the major hurdles, but have to get into the SDN frame of mind. As an old (and very stale) Cisco guy... I have to change my way of thinking.... ( some stuff doesn't seem to map logically in Omada either, like my OC200 has a static reservation but yet it's pulling from DHCP....) that stuff messes with my OCD. 

....Almost as bad as a firmware update that vaporizes a brand new device....

  @KillerMBunny 

Good to know someone from the support helped out. Just bad luck to get a DOA. Hope you can enjoy future time with Omada.