No valid slot or error booting boot.img

[ErikChevalier]

UBports Installer 0.10.0 (exe)
Environment: Microsoft Windows 11 Education 10.0.26100 Windows 10.0.26100 x64 26100 0.0 NodeJS v18.12.1
Device: sargo (Google Pixel 3a/3a XL)
Target OS: Ubuntu Touch
Settings: {"bootstrap":true,"channel":"20.04/arm64/android9plus/stable"}
OPEN-CUTS run: N/A
Pastebin: N/A

Used google flash tool to reset phone to 9. Set up phone, enabled dev mode, unlocking and adb. Followed directions in Windows UBports installer. Unlocked bootloader and followed instructions to select recovery mode. Phone was stuck in Google start screen for an hour before I manually rebooted. Now stuck in Fastboot mode with error booting boot.img