Note: This does work on ubuntu 20.04 (focal) so ubuntu22.04 (jammy) in particular is misconfigured in your pipeline. After some investigation is seems that the “Packages” file is zero bytes which I suspect is the root cause. Link to file: https://repo.percona.com/ps-80/apt/dists/jammy/main/binary-amd64/Packages
Linux Mint isn’t in the list of supported platforms. So it might work incorrectly.
Proxysql package is available for jammy. As a part of distribution release it will be available in the upcoming 8.0.30 release.
If you want to have a standalone proxysql installation without PerconaServer for mysql on ubuntu Jammy you can enable proxysql repo: sudo percona-release enable proxysql release && sudo apt update