😄 I use the dark theme as well. I've gotten so used to the way the logo looks with this theme...

The thought comes up from time to time about whether a lighter colored background should be used, or just replace the logo with a new design. If giving it a background, I would like it to look intentional so that it can frame the logo in a presentable way. A white rectangle on a dark background would look unprofessional. But maybe it could be ok with rounded corners or some kind of border? The solution doesn't seem obvious to me.

I agree it is not as straightforward as it sounds, and I am no artist/UX design expert.
Maybe for your next release announcement you can ask Reddit (or the community at large) for help or recommendations.
The pixelated Ferris looks really cool though, this little guy should stay!

I have a "mitigation": it turns out there is also a "dimmed dark" theme, which is a nice compromise for my eyes, and the logo looks rather good on it. Really the minor annoyance only appears with the true dark theme, which is just too dark anyway. We could argue it's an "upstream" problem.

I switched to the dimmed dark theme and agree it is much more pleasant in general. Also here is what the existing logo looks like on this background, for comparison:

I'm keeping this issue open since I believe there are improvements that can be made to the logo itself. I just don't exactly know what those would be right now.