First install the transitional updater, fixes/Updater-v6-to-v7.apk · master · ota / ota · GitLab .
Then launch the updater and make a local update by clicking the 3 dots upper right and choosing “Local update” with the .zip file you downloaded.
After update and reboot remove the transitional updater by holding in the updater icon > App info > 3 dots > Uninstall updates
Pixel 7 (panther), panther/iode-7.3-20260307-panther-ota.zip · master · ota / release · GitLab
Pixel 7a (lynx), lynx/iode-7.3-20260307-lynx-ota.zip · master · ota / release · GitLab
Pixel 7 Pro (cheetah), cheetah/iode-7.3-20260307-cheetah-ota.zip · master · ota / release · GitLab