@Moem Great suggestion.
Since I am newbie, I did not think of this.
Also, I thought maybe I am doing something wrong.
Thank You

I deleted it after reading that Libertine is on its way out & Snap now supported, so I installed the snap version & it works OK- wireless external display - 4K TV.
Also connected $10 (USD-Amazon) Acasis USB-C port expander to charge and plug in USB Keyboard & USB stick (with *.ods test file).

@kugiigi said

I don't understand why they even care where you bought it. Unlocking bootloader factory resets the device right?
It's not like you're using it to access data from a stolen device..And you'll need access on the device to even allow unlocking

On my previous phone purchases (6 google Pixels, to install 5 LineageOS & 1 UT), I was aware I needed to buy 'Factory Unlocked', and not originally sold by Verizon or AT&T, because they refused to unlock bootloaders.
My guess is that, at least partly, they realize that by installing 3rd party firmware, we extend the life of the device and put off buying new ones.
I read what I could find regarding Oneplus, and it looked as though, as long as carrier was unlocked (which implied phone paid off), then Oneplus would unlock bootloader (for T-mobile sold models).
I discovered that, at least in my case (BE2028), not always true.
[Since this failure, I searched info for other possible UT candidates, and read that Xiaomi is less helpful for unlocking lately].
I also discovered (sadly for this UT project) there are far more 'factory unlocked' Pixels available used than Nord N10's !

@RapidRotator said

Anyway, I don't have a Miracast, but I can cast Jellyfin to my Panasonic TV with does 1080p with perfect quality from my N10.

I just looked up Jellyfin. Seems to be different from UT Miracast over WiFi.
Miracast is system built into many TV's since it launched in 2012.
From what I recently read, cell phone running UT talks directly to the TV via WiFi.
Limited though, 1080P max, even if you have a 4K TV. (Looks usable though).
I also read that since Google Chromecast came out, Google reduced Android support.
Also, I think no Miracast support on Google / Android Smart TV's (not positive of this).

@ChromiumOS-Guy said

@oldbutndy download the EU firmware (EOL) and the real firmware for your version for EOL, then copy the identifers in the scatter xml file from that version to the EU one, then flash through EOL phone will check see T-mobile or whatever it is you have pass the check and flash EU rom with unlockable bootloader worked on my N100

Thank You. I read a bit about this option, not not enough for confidence yet. I am still within return window for ebay, and prefer not to mess up the phone in a way I can't restore to what seller sent me. I am new enough that I expect that is possible, but not sure I, personally, won't screw it up. I will read more.

@vverve Yes, I am trying to pinpoint specific issue also, so as not to waste time in future: Mine, sellers, and others who read these posts.
I never activated on T-Mobile directly, but bought a T-Mobile SIM via MVNO (USMobile), & configured on the Pixel 3A (Android 12 stock) first (I think).
I asked Oneplus if they could provide more detail, but they did not.
I read about the government customized issue, and also 'black listed' issues. The IMEI checking webpage offered black list checking, but for a $ fee, so I did not do that.
I also read that Oneplus might refuse bootloader token if someone else had previously requested unlock token. Maybe my phone had that problem.
The easy unlock model BE2026 seems extremely rare on Ebay, and Facebook marketplace is challenging to search (random results - high quantity to review - mostly not even Oneplus, or Nord, or N10, depending on what search terms you try).
I really hope UT developers get OP 8 series working, just to increase number of possible devices to try (but a recent AI answered suggested 'late 2026, maybe').
I even considered a Braxphone 3 listed on ebay ($400 !), since I read they recently got UT basically functional.

@vverve Does UT use a 'location' setting like Android, so that it automatically prefers WiFi over cellular, When at home (or other good WiFi place) ?

@vverve Good suggestion. I just did it. Not reported lost or stolen. I had not done this previously because I purchased from Ebay seller whose main business is cell phones, over 30,000 transactions and almost 100% feedback. So, they seemed quite reputable. (and have been great at communication).

@rocket2nfinity said

Another user's experience:

https://alaskalinuxuser3.ddns.net/Ubuntu Touch works on AT&Ts whitelist.html

Thank you for more info. Reading through that link (nicely detailed), it seems similar to my experience, except that Oneplus accepted his proof of purchase, but rejected my request because it went through Ebay.
I will ask Oneplus:
If I buy from private seller, will they unlock bootloader ?
Will they accept DIY bill of sale ?

@vverve I did get a lady this time, but unfortunately got same answer: NO unlock token.

I just searched ebay again for BE2026. Ebay shows many listings, but reading the details -which half the time don't state the BE20nn number- in each listing istedious day after day and almost all are BE2028 (T-Mobile), and occasionally Metro.

@vverve said in OnePlus just informed me they will NOT unlock bootloader for a device on bought on Ebay.:

I can confirmed , received today from oneplus support an unlock token for a second n10 5 g devices bought on ebay .
Patience i've kept , i did wrote them a long reply about such policy vs the potential reluctance it could introduce to buy Oneplus , used or not . Did sent a link to here ...community wonders .
Got friendly support of their escalation department .

OK. I will try again. Thank you for update !

@kugiigi said in OnePlus just informed me they will NOT unlock bootloader for a device on bought on Ebay.:

@oldbutndy Just to set the expectation. Do not expect much from the external display experience. At the moment, it's kind of regressed compared to xenial and older versions. It has been better now in Noble but it's still have lingering issues and the most notable and experience breaking one is mouse scrolling. It doesn't work properly in the browser (only one tab or webview works) and scrolling in native apps is too "momentum"-ish
In any case, it's still fun to use from time to time. In fact, I'm using it right now to test some things

Thank you for details. My test was very quick. I think I played a video for a few seconds. Then Libre office spreadsheet, mostly just to see if it would open up a file I had created on main PC, using same TV as display. It did. so, it was kinda fun. The only thing I remember from that quick test was a mild 'wave' rolled down screen, kinda like refreshing screen. usable.
Not expecting everyday use.
I will test more, & take notes, as soon as I get a working UT phone again.

@gpatel-fr said

you can lookup on the profile if the person has recently logged in. AFAIK there is no email notification for a chat, one sees them when logging on.

OK. I will check periodically. Thank You.

@rocket2nfinity said

@oldbutndy - there are two OP 8/T/ Pro ports in progress.

I read your links, searched for others.
Tried a 'chat' with the person who said they are helping test (no reply yet).
But, I did not find comments where I could 'reply' or 'quote' and ask question. I did not try Telegram yet.
If you find any updates on OP 8 series, please let me know.