[Sunspark]

This is OK for me because I use these with full (or medium) hinting and anti-aliasing off in some apps, and greyscale anti-aliasing in other apps with the v35 interpreter.

v40 with slight hinting and greyscale or subpixel works, but I don't tend to use the fonts that are meant to be used with slight hinting and later fonts can't handle anti-aliasing off at all.

You can easily do this on a per-app basis with flatpaks.. you can set an environment variable with flatseal, and you can drop a fontconfig folder with a custom fonts.conf in the flatpak's var directory.