3rd part calendar-app that can access the entire Calendar database on iPhone

It has been claimed here that there is a simple workaround for Apple's 1 year limit for finding events older than 1 year when performing a Search using the Apple iPhone Calendar app. According to this apparently incorrect information a Search using these 3rd party calendar apps will find events older than 1 year. Only a single 3rd party calendar app was suggested by the user, but it was claimed that there are several.

I have tried the one suggested and finding events older than 1 year does not work in it. I tried Google Calendar and finding events older than 1 year does not work. Have now deleted both. What are the names of these calendar apps that somehow get around Apple's at-most-1-year-ago Calendar Search limit - how does one find these apps? They're not in the App Store on iPhone 12. Has anyone else tested any of these? Results?