I have a Pixel 3a XLthat is currently running CalyxOS. I want to move to GrapheneOS.
I've got the bootloader unlocked and sitting in Fastboot mode.
I've downloaded the GrapheneOS install and have adb and fastboot on the Mac.
Every time I try to run ./flash-all.sh, Terminal states fastboot not found.

Am I doing something incorrectly? Do I need to have adb and fastboot somewhere in particular?
Is it inadvisable to try this with CalyxOS installed?

    Shmop_Shtop you haven't followed the instructions to the letter and haven't set the PATH correctly. ADB is also not required to flash.