Install by putting the RDR1 Font folder in your lml folder, if you using the Original RDR1 Pause Menu, replace it's stylescatalog with the one from here, or the fonts will be really tiny.
This was pretty fun to make, it's still not done yet. Keyboard prompts work differently (swf/gfx) so that will need to be updated, but I think it's in a decent enough state to release for now. Includes support for playstation/stadia controllers, some prompts had to be re-created. Font was really hard to find, looked through over 300 pages trying to find it since google is actually useless if you search RDR1 Subtitle font. If you're curious. The font is Mouzambik and the f,e and g needed to be changed to alternate versions that thankfully came with the font.
Fallback font that gets used in case of missing characters is the catalog font.