Japanese here. There are specific editors often categorized as “アスキーアートエディタ” (Ascii Art Editor). They often come with libraries of existing AA to modify, and can display image with low opacity to “trace” image.
Large part of jp ascii art made/appeared in 90s to early 00s at underground forums like 2ch. Those editors were tailored for their speifics such as font family (MS-P Gothic) and size. The display/font system is different nowadays, but unlike “AA artist” in those times who is 100% comitted to make vertical line aligning pixel perfect most of people find those AA displays ok.
I don’t know where you get the information tho, it’s factually false.
Japanese have have /h/, /ç/, /ɸ/ consonants in ハ行 (written as ha - hi - fu or hu -he - ho but pronounced differently). The consonant /ɸ/ is generally transcribed as f in alphabet.
フ(f+u) is the only letter that pronaunce /ɸ/ in regular ハ行, but ファ行 (f + other vowels) indicates sounds with /ɸ/.
Transcription of wifi in Japanese is ワイファイ, not ワイハイ.