abednego When he says "that's not a great symptom" I think @de0u refers to a possible failure in the internal storage of your Pixel 6 smartphone. Hope being wrong here, but it seems your Pixel may have a hardware failure.
Sorry, I was in a hurry.
There are various sorts of file-system corruption that can come from various causes. Running the battery flat may result in corruption of the user data partition. Hardware failure in the flash storage can also result in corruption of the user data partition, so it can be hard to tell the two causes apart.
But the red "corrupt" screen means that there is an error in the system partition, which is read-only. The A/B update system is supposed to ensure that both the old and new system partitions are valid or else it should cancel an update and try again. If the red "corrupt" screen suddenly shows up, that is unfortunately fairly likely to indicate a hardware failure in the flash storage. If that's what's going on, flashing an OTA image (either over USB or letting System Updater do it) might possibly resolve the issue, but maybe not. Regardless, if one part of the flash goes bad then maybe another part is about to.
Overall I think my first move would not be trying to store anything to flash storage (installing an update involves storing a lot of data); I think my first move would be backing things up. And I would be nervous about the device for a while even if it seemed to be working ok.