Bug Font.HasCharacter breaks with many Chinese characters

I found this bug today: https://issuetracker.unity3d.com/is...-false-for-some-uppercase-cyrillic-characters

Did Unity ever provide a rationale for why this is listed as "won't fix", or what a possible workaround would be?

I have a huge list of characters that exist in Simplified Chinese (around 8400 chars), but I don't think my calligraphy font supports all of them. I'm trying to figure out which chars are missing from the font, but the Font class itself is apparently not capable of doing that.