Andor's story is likley isolated enough that any "legacy" changes it effects, probably has little effect on continuity (even less Skywalker/Jedi specific saga) , and likley more has to do with just how we
perceive the Rebellion at the time.
For me it only adds to the show's intrigue, and makes Andor an even more fascinating POV character.
"But Cassian is also a natural leader. “He’s seductive,” Gilroy adds. “Seductive in a way where he’s manipulating people. He compromises, he changes his mind. He’s really a perfect kind of spy, warrior, killer. How do you get to that place—and then sacrifice yourself?”
seemingly suggests that Andor will be two seasons at most. If the second season takes Cassian Andor’s story up to the events of Rogue One, then there really aren’t many places left for the series to go.
Yeah I'd take that with a grain of salt, as it's just broad-stroke indicating where he will end up.
Still could tell stories while he's already entrenched there, if they have more.
The actual quote -
“It is a second season, but it’s really, for me, the second half of the novel,” Gilroy says. “This first season is about him becoming a revolutionary, and the second 12 episodes take him into
Rogue One.”