This to me is a testament to the fact that most buttons should actually be text unless extremely common like the hamburger menu, but even that's debatable.
I agree, especially on mobile (even in 2020, many users — who often just got used to the hamburger menu — don't realize that the vertical ellipsis is a symbol for "menu" or "more options", it often just looks like a random decoration to them), although on a desktop website or app you (hopefully) have the option of hovering the mouse pointer (even accidentally) over any unfamiliar bit of UI gubbins to get a clue.
I'll note though that the specific example of "文A" is, in fact, a text label. The first Chinese glyph even translates as "text".
Only in the sense that those glyphs are used in certain writing systems. It's not text in the more important sense of expressing a linguistic message. It's just random characters. "文A" is a text label to exactly the same degree that ":-)" is a text label.
Note in particular that the Chinese glyph does not translate as "language". That would be 语/語. As you accurately note, it translates as "writing".
It's standing alone here. I'm aware of words like 文明 and 中文, but here are the 14 glosses for 文 in the 现代汉语规范词典:
1. (verb) to tattoo or paint patterns or words onto a body
2. (noun, literary) a pattern, particularly as of wood grain
3. (noun) ancient rites/ceremonies
4. (noun) non-military affairs (opposite of 武)
5. (adjective) gentle; not fierce
6. (noun) indicating phenomena of nature or of human society
7. (noun) writing
8. (noun) an essay
9. (noun) the humanities and social sciences
10. (noun) an official document
11. (noun) Classical Chinese (the language that is to China as Latin is to southern Europe)
12. (measure word) used for the copper coins of traditional China
13. (verb) to cover; hide
14. A surname
Most of these senses come from words that include the morpheme 文, not from uses it permits alone, but "language" is still not even listed.