Apparently, there are other active mods that may contain these 3 files:

1. clientscheme.res (mostly found in UI or HUD only mods)
   
2. l4d360uischeme.res
   
3. chatscheme.res

Info: The 3 files above manage schemes such as colors, fonts, borders, controls, etc.

as far as I know in L4D2 if a mod conflicts like this there are only two possibilities between the files from this Mod being replaced with your mod, or your mod being replaced with this mod.

if your mod will be replaced with this mod, it is certain that the font does not change because the file from this mod is not executed because the file is replaced by the file from your mod,

but what if the mod I'm using has a scheme file too, you have to edit your mod's scheme file first, and change the fonts, with the code available in the BF Modernista Fonts mod.

some tools I recommend:

• GCFScape
  
• VPKedit
  
• Visual Studio Code, or Notepad whatever text editor