I got it to work using redesign Reddit! However, it works very weirdly for me. Firefox 104.0.1, Windows 10.

When I uncheck only "user scores" to hide it (that's the main thing I want hidden), but leave everything else checked, instead, everything gets hidden.
When I uncheck both "user scores" and "arrows" but leave post and comment scores both checked, arrows actually show up, but everything else is still hidden. I'm happy to use Reddit like this, but it's clearly not operating as intended lol.
When I uncheck everything, which is supposed to hide everything, it actually makes everything show again.