Hi Beth,
You didn't mention, is this an aftermarket screen or a genuine Google part?
The thing is, I have noticed a disturbing tendency for people to report genuine Google replacement parts that don't work. For some reason it seems to be much more prevalent for Pixel phones than most any other model I've seen when people buy genuine factory replacement parts, which leads me to think that Google has some kind of quality control issue with their replacement parts.
If you bought the screen from iFixit, it will be a genuine Google part, as that's all they carry for the Pixel phones (I have the 6 Pro myself). Their screens have a lifetime guarantee.
My suggestion would be to unplug the replacement screen since you fortunately haven't glued it down yet, and plug the old screen back in. If the original works the same as it did before then there's a fair chance the replacement is defective and you should look into getting a replacement.