For example, some fonts render A in a way that looks like Cyrilic Л. (Like The Mandalorian title screen.)
This would be incorrect if using the same A for both: https://i.ytimg.com/vi/V8fC7bdV-mI/maxresdefault.jpg
(probably not what you meant, but just in case: the fourth letter is not a Cyrillic A but a D.)
you can see that the A letters are rendered the same as Cyrillic Л.
To further the confusion, in Buenos Aires there are many street signs that use Л as the letter A, and they use П as the letter N.
Exactly. It is more often rendered like that in Bulgaria. But it is still the letter Л.
Which just furthers the point that glyph rendering and character code points are very different problems and the multiple code points in Unicode are the right approach.