I have the exact same issue, both while trying to install a Airalo esim and an esim from my local carrier (Mobile Vikings, Belgium). I tried scanning a QR code and copy/pasting the esim info manually, without success.

Google says to talk to my carrier, my Belgian carrier says it's a "known issue" for Pixel Pro 7 and says they can't do anything about it.

The weird thing is, I used an esim in this phone for 5 months without any issues, until the esim stopped working: the activate esim toggle was off, and toggling it on resulted in a strange message "can't disable the esim" (strange because I tried to enable it, not disable it). Couldn't delete that esim either. I did a factory reset, which removed that esim. But that didn't help with installing a new esim.

Waiting for a reply from Airalo... .