First, I find the expansion carets to be very difficult to see while using dark mode. See attachment. A higher-contrast color like white/orange would be useful, and hopefully an easier fix.

Secondly, I feel that it would be useful to have some sort of dotted lines from Parent Projects to Subaction(s). See second attachment which is my mockup.

I feel both of those visual indicators would help users in many ways, and help with accessibility as well.