It works when I do Insert > Special Character but when I input it using a formula =CHAR(252), which is the check mark symbol in Wingdings, it shows a “missing character”. I have ttf-ms-win11-auto installed.
wingdongs.ods (8.7 KB)
Version: 24.8.3.2 (X86_64) / LibreOffice Community
Build ID: 480(Build:2)
CPU threads: 2; OS: Linux 6.6; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US
24.8.3-1
Calc: threaded
What do you expect by using CHAR, which by definition depends on some “current code table” (what “code table” do you think is “current” for you on non-Windows system?) - why not use UNICHAR?
Why does 32-126 works with CHAR though?
Because these are stable across UTF-8, and most 8-bit encodings (so-called ASCII). Do you intend to learn the history and theory of text encoding here? 
Gotcha.
No no no, I don’t want to bother you any further. 