Here’s my take on this.
Finding a hidden Cydia installation involves a few different approaches. The simplest method is to use the Spotlight Search feature—just swipe down from the middle of your Home Screen and type “Cydia.” While this can sometimes be masked, it’s the quickest initial check.
A more reliable method is to connect the iPhone to a computer and perform a backup and restore via iTunes or Finder. This process will completely reinstall the iOS software, effectively removing any jailbreak and associated apps like Cydia. The obvious trade-off is that it’s a complete reset, so ensuring your data is backed up first is crucial. It’s a thorough solution, but it requires more effort than a simple on-device search.