Pamac 10.3.0-1 invalid or corrupted package Clean preinstall

You have to Yes to all, and regarding those PGP signature outputs, there are a couple of topics in the forum about

The current install is not broken, the system is not corrupted. It can be easily mitigated and there is no need for new install. Just follow the instructions. In time you will understand why it happens, how to deal with them if will happen again …