Unable to change Gamertag and haven't had any success with support.

I'm at my wits end with Microsoft support and looking for advice on how to get my Gamertag changed, because what really should be a trivial issue is driving me crazy. Here's my issue: I just want to change my gamertag. The complication is that whenever I attempt to do so, I just get looped on the gamertag page. I have tried everything I can think of:

* Multiple browsers (Firefox, Chromium Edge, old Edge, IE, Chrome, etc.) on Windows 10, Windows 11, and on an Android phone on multiple networks (home, work, LTE/cellular, and VPN). Cache cleared. Extensions turned off. All the obvious stuff has been tried, and it's all just a big ole loop.
* I have been trying to change my Gamertag since roughly November of 2021 on and off, so it's certainly not time related
* I can enter gibberish as the gamertag, but it'll still loop - whatever Gamertag I attempt to use will have no impact on the attempted change
* I have gone through every single sort of toggle and switch in the various privacy menus and everything else that has been asked of me by support at one time or another
* The gamertag page says I still have a "free" gamertag change, but honestly, I'd happily pay money just to get this fixed from the time it's taken
* I do not have an Xbox anymore, so I have to change my account online. I

have gone through MS support chat and called into Microsoft either 5 or 6 times now. Most of the time, I have to spend a bit of time entering my info, going through the obvious troubleshooting steps over and over with each customer suppot rep, and then ultimately they put me on hold and tell me to wait. The one time I finally got escalated on the phone to the more senior technical team, they said "the system is down" and they cannot help me and told me to try again another day. They didn't offer any way to expedite the process either, so I go all the way back to dealing with another new MS support rep. Most of the reps I ahve spoken to have told me that they're going to elevate my request and contact me via email within 5 days. I have yet to receive a single follow-up communication. Not a single time. I've tried providing two different emails and I diligently checked the spam filter too - I just never got a follow-up at all. The most frustrating part of this is that I saved a ticket number of one of my requests, and when I finally convinced someone to look it up, they said it had been closed. It was reference number 1530035898 if anyone has the ability to check those. I feel like at this point I've wasted well over 10 hours of my life trying to change my gamertag.

As for the issue itself, I am fairly certain the problem is due to an illegal character in my gamertag, which is "| Hans |" with two pipes (|). You can't use a pipe in a gamertag anymore, but there were no such restriction at the time when I created that specificGamertag. If I open Chrome Dev Tools, I see my request return a 400 error page. The error message is "{"source":"Accounts","code":1372,"description":"The gamertag belongs to another user","data":null,"traceInformation":null}". This error message says the gamertag is already in use, but even if I enter gibberish to get a totally unique name, I'll still get this same error code. I have also seen an error message indicating "code":1024,"description":"Another operation conflicted with your request". I also created an album showing the loop and error pages. Sorry for the low rez on the video, but I included screenshots at higher res that show essentially the same thing: https://imgur.com/a/H6FWRnr

I'm just out of ideas as to what to do next. I just want to change my gamertag, and it's proving to be a nearly insurmountable task. I don't care if I have to pay for it, or even if I have to change it to a temporary tag and then pay to change it once more to a tag I actually want. Does anyone have any tips or hints to point me in the direction in a way I can take care of this?

:)