So I've fixed this issue after tinkering with it for a very long time, the bug is that tmExternalLeading is computed via max(0, lineGap - ((winAscent + winDescent) - (Ascender - Descender))), Windows GDI returns 0 when (winAscent + winDescent) > (Ascender - Descender) however Wine is returning 46-154 for this game leading to the font scaling issue. This appears to be common with CJK fonts although I haven't seen this issue in any other software.
The issue can be seen here: https://gitlab.winehq.org/wine/wine/-/blob/master/dlls/win32u/freetype.c?ref_type=heads#L3398
Hello @Renari, it might be worthwhile to report your findings to upstream wine after reproducing the issue with vanilla wine. If a fix is merged into upstream wine, then make a note here and a Proton dev can consider a backport to Proton.
I've opened up an upstream PR here to fix this: https://gitlab.winehq.org/wine/wine/-/merge_requests/10603
Nothing extracted yet.
Compatibility Report
System Information
I confirm:
Proton Log: steam-959880.log
Symptoms
Text scaling issues


Reproduction