...they do though...? メ is [me], which would've been used if the author wanted her name to be amelia. but he didn't, he used べ which is [be]. n and m are only really interchangeable with ん/ン, but that's because when it's used the pronunciation wouldn't differ regardless (like nipponbashi vs nippombashi, tenma or temma, to use train stations as an example). furthermore, localization is used when something that's japanese can't be directly translated to a foreign language like english. localizers should not be changing any proper nouns unless they just don't work/make sense. that's overstepping.
The point of mentioning all that is that there are other examples of how they can be interchangeable as well as differentiated depending on the grammatical rules, but the entire point is predicated on how b and m is not as easy for Japanese speakers to differentiate. So the be, yes I know it's be, could've been used to refer to Amelia instead of the transliteral Aberia if the author made that common mistake in Japan.
Localization is standard practice in translation as a profession btw, it isn't limited to just Japanese and English, but the whole process is to turn foreign colloquialisms and cultural differences, and in these larger differences how they spell foreign names (misura, sifu, patorikku, and morisu) and cultural implications, and then turn it into local counterparts or what is closest to them, which in this case would be to English. That is why it's called localization. There's no exact line where something is done wrong per se, but the purpose of localizing translations is to make reading or hearing it into what is closest to something written or said in their own language as a reader or listener.
To translate Japanese transliterally would sound very off.
Also, wordplays are sometimes impossible to translate into a fitting localized wordplay.
So to "localize" it to Abel(r)ia when translating into English, makes less sense than Amelia.
is mithra a japanese name? is sif? is patrick? or morris? or half the characters in this series?
The point of specifying how Abel(r)ia isn't a name for a person in Japan, is that people keep using the flower as a point of reference, with the implication that it'd be like how Rose in English is also a name. Misura however, which here has been localized into Mithra while in the Crunchyroll dub has been localized into Mizra, is an example of how localization doesn't always have a clear answer even in the professional space. Viz Media is infamous for failing hard with localizations sometimes. The most blatant mistake I can think of right now would be how One Piece's Zoro has been localized in the professional space to Zolo sometimes. Zolo isn't technically wrong, but it's not exactly proper localization either.
So making clear it's a foreign name used, do you really think the Hebrew name which is very rare in modern times was used on purpose, or that it's simply the author mistakenly believing it's a b instead of an m in the much more common Western name Amelia? (Not to mention how her last name is clearly British.)
And in general to be sticking too close to the transliteral will sound off even if that is what was meant, so that's where localization would bring it closest to but is not required to be the exact same because there's no requirement for localization to make it transliteral.
Which is even assuming that was what was meant, because due to that massive language barrier being so common in Japan and in its education system, and b and m being so hard for them to differentiate, it could've also been just a mistaken understanding by the author who could've thought it's supposed to be a be there (there are schools that forces the English teachers from overseas to be teaching the Japanese norms of "English" instead of the actual language, although there are also those that provides more freedom for them to teach proper English).