No, now.
Their reporting is really solid, but because they don't push thin stories that are pure conservative propaganda, you call them biased.
They used to be considered conservative propaganda, but that wasn't really true. They just mirrored whatever story the White House wanted, and that was support for the war. That wasn't conservative, that was everyone.
Conservatives don't like NPR because they don't publish bullshit conservative stories like the lab leak or Hunter's laptop. If you had any understanding of journalism you'd appreciate those aren't responsible, substantiated stories. Even now when someone publishes that a leak is "possible" conservatives claim that's a confirmation it happened.
If you want to insist they're biased, provide a few examples of biased stories they've published and make sure those stories are false. Your best bet would be a Rittenhouse story, a lot of the media got that wrong. I doubt they did but it's definitely possible, especially if their staff is predominantly liberal.