Why wouldn't she just use your last name when you got married? Seems like a pretty simple solution.
There are laws in France from revolution times [0] that basically set your name in stone because anyone using whatever name they liked without need for any paper trail basically cause administrative and bureaucratic hell.
But nowadays even the administration works around that to comply with the tradition with things like "nom d'usage" (you can see it as "lastname nickname"), which is basically allowing you to use another name for non-legal purposes, but people still think it's legal and shove it in every form as regular "nom".
I repeatedly heard from people working in HR that a significant amount of the questions they get the first few months of employees are just (married) women complaining about their last name "being wrong" on their payslips simply because they think that's no longer their legal name though it is.
[0] Loi du 6 fructidor an II (August 23rd 1794), liberal translation of article 1: no citizen will carry any other name than that of the birth certificate.
The point being, reactionary bigots tend to out themselves, and that's the obnoxious worldview driving by here. Erasure of someone's identity in conformance to external expectations is something that - remarkably - remains a thriving and actively promoted idea. This makes it all the more important to confront and openly, firmly reject.
So is changing her name. But people shouldn't need to do gymnastics for such a trifling matter. This is like cutting a foot to fit a shoe.
Cultures have different naming conventions, and not all cultures pressure women to take names from husbands.
The real simple solution is to accept that the common ground of name form is a string. One string.
In an English speaking county, having a separate surname aids in sorting and presentation of family unities. The character set is typically A-Z. In Spain e.g. one expects a person the have two surnames. The default — but this can be changed – is that first name is from the father and the second one from the mother. By looking at the order of your name you can get information about family structures. Character set is A-Z + Ñ + umlauts and accent marks.
Going to an English speaking country I could expect them to spell my first name correctly; but since it contains a character outside A-Z I change my name to comply with their modus operandi. Yes, their computer system probably supports UTF8, but most people have never heard of this character and you won't find it on their keyboard. No problem, I change my name to comply with their system.
In Spain official forms often expect two surnames and certain characters. No problem, I use an extra hyphen, change my name, use my middle name as a surname or whatever makes the system happy.
Is it perfect? No. Does it really matter? No. So I just respect their customs and get on with my life as a respectful guest in the country where I am living.
The problem is it's every SaaS online service in the world many of which happily do business in Myanmar. You can't just tell an entire country with its own unique culture and 50 million citizens "FU, you're wrong", and when you do, it's you that's wrong not them! Everyone from Facebook, LinkedIn, Google, Microsoft, Amazon, to federated platforms like Matrix or Mastadon, to developer tools, to every forum on the Internet [1] requires a first and last name! These platforms have literally millions of users or customers around the world - and at least one entire country - that don't fit the <first> <last> mold and I find it highly disrespectful to force it on them like this.
[1] My info might be out of date on some of these as I've been out of the country and not paid much attention for a few years. I would hope that by now at least some of these big multinational companies would get it right. However, suffice it to say, the vast majority of SaaS platforms today are disrespectful to people with one name.
However, I don't see how if a person has no first/last name, and expects to be referred so, can be construed as disrespect to the English-speaking culture. There is no need to learn another language; all it takes is to "know" that the person has one string as a name.
You said it helps with sorting, and that is exactly why I said cutting a foot to fit a shoe. It's asking people to change their name for the sake of paper work.
I don't expect to show up and make a country change, for the sake of me. My name is already in first/last form.
I wish countries, and systems (frankly many of which are expanding to be used worldwide) to change, because I believe it to be the right direction, and in the end will save everyone's time.