Lizzid Peeple!
But I agree that that they'd be flightless bird people. Birds are the only other bipedal animal outside great apes and marsupials. Though the Kangaroo Beatniks of The Tank Girl Universe are a possibility down the line too...
But there is a point where progress plateaus. Like with things native to Florida. Alligators and crocodiles haven't really changed much in 80 million years.
They survived the KT boundary because they can go a up to 3 years without food. So while the other reptiles, even
the cunning raptor met their fate, the aligators and crocodiles just waited for any remaining raptors to die near the waterline. And we're not part of the extinction event.
But any reptiles that stayed closer to lizards probably didn't evolve bipedally because their current form got them through an extinction event. Apex reached.
Parrots and Corvid might become a dominant species. I just cant see them being able to build much with tools held by their beaks. They fish for bugs pretty competently though. And their bones hollowed and turned to wings long ago. No need to go back, is there?
Animals only give up flight when its better. Like the ancient
Procellariiform which diverged around 60 MYA into albatross, petrels, and penguins.
One decided it wanted to soar forever, and another said it wanted flippers to focus on the water.
So, while i cant totally rule out there possible could have been a reptile that went underground, like proto moles, It would take a complete behavior change, and would have required an established above ground (heat rocks for all!) advanced society. Because animals without the abstract understanding and higher complexity wouldn't naturally run away from their instincts in crisis. No lizard is running from sunlight without an understanding of asteroids and impact winter.
Any proto-placentals and reptiles that survived had behavior and tactics that were already tailored for that armegeddon.