Installation on FP5 - stuck at flashing both on Win11 and Ubuntu

Edit in light of your added:

I think all this really tells us is that you can lock and unlock your FP5 on this machine with fastboot version 35.0.2-12147458 but the script is failing to run with fastboot version 33.0.3-8952118

So (another edit) the following suggestion may not be so attractive … hmmm

Am I right to say that platform-tools is not system installed on this machine?

Are you drawn to the suggestion to

… and the aim would be to provide fastboot form /c/platform-tools …

Edit for clarity perhaps as Adding adb path to the environment variables.