the darkened secondary color is nice. It is still quite a blue purple.

I've been using #9333ea for purple, which is a similar contrast but much less blue. Maybe it is a bit inconsistent?

Do you think the fact that it doesn't work well on black / white is a problem? The logo needs to work well on black and white. I suppose it would be nice for screenshots to work well on black and white too.

The background colors used in gitworkshop.dev is part of the charm of the current design aesthetic. Maybe it time for the color scheme to mature a bit.