I can (and do) just read the ~/ssh/.config file if needed, it’s quite legible. In most cases however zsh autocompletion does all the heavy lifting for me (ssh ser(tab) -> ssh servername).
Still a cool idea for a script, and if it works well for you more power to you, just saying there’s more ergonomic and universally applicable solutions. (Only mentioning this since you said “I couldn’t find a decent solution to this problem”).