2019 Intel MacBook Pro 16" will only install Catalina.

6. Used my other MacBook to update the firmware from DFU mode in Finder, again successful, again no go on the install, again trying Revive and Restore.

7. I have run Disk Repair | First Aid on every volume/container (showing all), and no errors are found.

8. I have run hardware diagnostics with no problems found. This does not surprise me because Catalina works perfectly - boots, everything works, etc. etc. so this was a reach to begin with.

9. Have attempted to install newer OSes in Catalina's Software Upgrade, through a local copy in Applications I downloaded from Apple's App Store, but USB within the OS and from Recovery Mode, even kicking it off in Recovery Mode via the Terminal. Nothing works.

10. The SSD has been Erased via Disk Utility and via the Recovery Mode Terminal multiple times, so there are no weird apps, no anti-virus, none of that stuff I have read about in other posts. Also note, based on other posts I found, I have tried formatting to JHFS+ (no expectations this would work) as well as APFS (every other attempt).

11. I noticed when installing from USB in Recovery Mode that the Wifi did not start. I thought maybe it was failing because it could not connect to Apple for verification/OS signing/whatever its called, so tried with and without enabling WiFi - no differences.

12. I took it to an Authorized Apple Repair Center (there are no Apple stores in the country I live in, but iHelp is a larger, very well equipped repair center here with several locations - not a guy in a shack on the side of the road, which also exist here - and in retrospect, may be a viable option) and they confirmed that there were no hardware issues, and they were also unable to upgrade the OS past Catalina.

At this point I am sitting here with a very expensive (2.4 GHz 8-Core Intel Core i9, 64GB RAM, 8TB SSD, 5500 graphics card) that is stuck on a 5 year old MacOS. I have tried to do as much research on my own before posting this, hoping to find a solution I could share and save someone else my pain, including this forum, Reddit, ChatGPT, etc., but unfortunately all attempts have been unsuccessful.

Can anyone smarter, and more experienced than me, or just lucky, see anything I have missed or have any suggestions? Anything I can post here to provide additional needed information? Any suggestions would be greatly appreciated.

Just as a side note, since I have seen other posts recommending "Send it to Apple for repair," that is problematic for me. Shipping from here is extremely unreliable, and I would have to wait until my next trip back to the United Stated, where I would send it off and either wait for a couple of weeks or pick it up on a later trip. Note that since AppleCare is not valid here, I did let it lapse a couple years ago and I called Apple...I was told the "repair" is to replace the mainboard. Given the specs, mainly the 8TB SSD, this would be thousands of dollars. I can replace the machine with a clean used similarly equipped box off of eBay far cheaper on my next trip to the States. This post is my last effort before considering this MacBook a lost cause.

If you have read this far, thank you. If you have any ideas, no matter how silly at this point, or some of that Certified Apple Technician magic, it would be greatly appreciated.

Thanks!

Thanks. That is really a bummer considering this thing was literally $7K out the door. You're not wrong though - Apple replaced my logic board only 3 months after I bought it in early 2020.