Ideally, you should have the printout. That's what immigration is known to ask for. Indeed, unlike visa stickers, which do not show up in the immigration system, e-visas do.
To immigration, the DTV is one type. To the MOFA, there are 2 different categories. Once you hold a DTV, it's treated the same by immigration regardless of how you qualified for it. You should stop making assumptions. If there is a difference in how immigration categorizes the DTV (highly doubtful at this stage) then this will be known in due course. As it stands, there does not appear to be one.
The Ministry of Foreign Affairs and immigration are NOT the same.
Nope, I'm afraid you're making assumptions again. The DTV is one visa type and there is no distinction to immigration, what category you applied under.
Yes, other places are better because they are less onerous. Laos requires 3 months of funds parked and possibly notarized documents in some cases (such as when documents are translated). Other consulates are much more easygoing.
I don't think there's a difference or that an immigration officer would see under what category you applied. That's guesswork on people's part, but I suspect that the DTV is just the DTV when it comes to immigration. How you qualify for one depends on what criteria individual consulates apply.
Now, if immigration could confirm what they see on their system I'll be happy to be stand corrected, but I am pretty sure I'm right.
If no one else can tell me otherwise, I'll ask the immigration officer what he or she sees when I enter on one, though I'll probably ask when I enter via land. I don't want to waste time at the airport when there's lots of people and the officers there are generally less chatty or personable.
Yes it's difficult...but keep in mind also, that unless the applicant is heading for Nigeria or somewhere like that to apply (the OP states that this is not desirable) then even getting a visa for Laos, Cambodia etc is as complicated as Thailand.
Don't assume nationals of countries such as Ghana can easily, or more easily enter Thailand than neighboring countries. It may actually be the other way round.
Also, Laos imposed a prohibition on nationals of several African countries entering in mid 2022 as a precaution against monkeypox. I have not seen any official notice stating that this ban has been lifted. Maybe it has been, maybe not (then there's the second WHO warning from August 2024, which may have influenced some governments to impose new restrictions).
Anyway, it's going to be tough. I can't really offer any more suggestions. The OP should try their best to convince the Thai embassy in the UK, since that's where he applied and where his wife is located.
Applying anywhere else sounds like it is fraught with difficulties.