8:30pm weeknight International flight from RDU: How early should we arrive @ airport?

Title pretty much says it all: Thursday night flight to Iceland (and then to Dublin), departs at 8:30pm. I’m assuming that if we get there at 6pm, we’ll be fine. Yes?? (We have TSA Pre and are not checking bags. The couple we’re traveling with may check a couple of bags.) Icelandair. Getting to RDU via Uber, so no need to park a car. TIA for your help/advice.