How can I disable ligatures in TextEditor?

[QYF-RYCBStudio]

Discussed in #431

^{Originally posted by QYF-RYCBStudio August 31, 2024}
When I use Jetbrains Mono to show the code, I find that they do the ligatures for most operators. But I can't find any property to disable it.
The Microsoft offical website says SetValue(Typography.StandardLigaturesProperty, false); can disable it, but I can't. (See https://learn.microsoft.com/dotnet/desktop/wpf/advanced/opentype-font-features?view=netdesktop-8.0).
Screenshots: