

SNW S1E2 - Children of the Comet. This is a tricky one because of potential predestination and the end result being an accidental major break of the prime directive. A warp capable civilization is certain that a comet must destroy a pre warp civilization and refuse to let that change. The issue is that the ship/comet wants the Federation to interfere and does not intend to hit the planet. This is all in Federation space.
Another in Federation space that is also a loose fit is LD S5E7 - Fully Dialated where the crew must recover Data’s head from an alternate reality that has fallen on a pre warp world. The loose fit here is that the only reason they count as external is that it is Purple Data who is not technically a a member of this realities Federation and thus an outsider.
Lastly a decent fit but outside Federation space is Prodigy S1E7 - First Con-Tact. The crew first breaks the prime directive by making first contact with a pre warp civilization but then defends it by stopping a Ferengi from influence the civilization negatively. This is outside Federation space though.
Every system is racist because every system is human and humans are flawed. Credit scores include systemic racism and banks making calls based on their gut is direct practiced racism. Systemic racism is much easier to slowly over time work out as long as you recognize it. But the only way to stop direct racism is to take at least some of the power away from individuals.
The systemic racism like the structural one in the argument can only be gotten rid of if you entirely removed the concepts of loans. The problem with that is it is impossible. The majority of the folks who have attempted to outlaw usury and loans entirely are not really looked back upon fondly in a historical sense.