I know quite a bit about Electrum private key, public keys, spending and storage in air gapped or hardware wallets etc, I just need to know how to trust a public key in Electrum on Linux Mint v22
What exactly are you afraid of and what do you think can happen after importing an Electrum public key into your new Linux distro? Since you said that you know quite a lot, then I am sure you know that having someone's public key can't help you spend their coins. Importing public keys is not a question of security and trust but rather privacy.