No pubkey / Jammy / 6.6 / repository not updated

[stevef]

I'm not sure how to fix the PUBKEY issue

It looks like you have at least two problems, as well as the NO_PUBKEY there is also an error caused by the transmissionbt PPA.
If you need any help with the PPA error, let us know.

For the google chrome issue, can you run a command to check the key on your system ?
Open a terminal by pressing Ctrl, Alt and T together.
In the window that opens type or paste in this command followed by enter

Code:

file /etc/apt/trusted.gpg.d/google-chrome.gpg

Please post back the outcome.