Sigh-Fi

No, you can't call Star Trek idealistic, or at least you can't contrast it to Star Wars as more idealistic.

Star Trek is VERY cynical about the capacity of humans and other sentient species to do evil.

1992

The Eugenics Wars (WWIII) begin.[14] At the height of his influence, the genetically augmented tyrant Khan Noonien Singh is said to be the absolute ruler of more than one-quarter of Earth's population. (WWIII is retconned to be in the 2050s by TNG's Encounter at Farpoint and Star Trek First Contact and to being a conflict separate from the Eugenics Wars; SNW's "Strange New World" retcons it to taking place in the 21st century, prior to WWIII.)

2026

World War III begins on Earth. Colonel Phillip Green and a group of eco-terrorists commit genocide that claimed the lives of thirty-seven million people. (ENT "In A Mirror Darkly, Part Two") (In TOS, WWIII took place in the 1990s and is established as an alternate name for the Eugenics Wars[14] while DS9's "Doctor Bashir, I Presume?" had the Eugenics Wars in the 22nd century. SNW's "Strange New World" retcons the Eugenics Wars to the 21st century, but prior to the outbreak of WWIII.)

https://en.m.wikipedia.org/wiki/Timeline_of_Star_Trek

Star Wars is far more idealistic, evil is about power and a cynical leaders that do anything to get more power... Star Trek has a consistently much more unnerving portrayal of evil as a much more nuanced force that is often irrational and difficult to resolve into pure pursuit of power that it is always attracted to it.