The warnings you're seeing are related to how your system is handling keys for software repositories and the architecture of the packages.
Firstly, let's address the key warning. The recommended way is to move from using the deprecated 'trusted.gpg' keyring to the 'trusted.gpg.d/' directory for storing keys. You can do this by re-importing the OpenVPN key into the new directory. Here's how to do it:
1. Download the OpenVPN key with this command:
wget -O - https://swupdate.openvpn.net/repos/openvpn-repo-pkg-key.pub | sudo apt-key add -
2. Then, delete the old key:
sudo apt-key del {KEY_ID}
, replacing {KEY_ID} with the ID of the OpenVPN key (you can find it with sudo apt-key list).
As for the architecture warning, it seems your system is trying to pull 'i386' packages from the OpenVPN repository, which doesn't support 'i386'. If your system is 64-bit, which is likely, you can safely ignore this warning. If you'd like to remove it, you can edit your source file at '/etc/apt/sources.list.d/openvpn-aptrepo.list', changing 'deb [arch=amd64,i386]' to 'deb [arch=amd64]'.