Where did the comic filter in Messages camera go??

Yep, the Feedback you sent is the best option for a feature request to have the Comic filter returned. It doesn't have to be limited to the Messages app and could be included with the other Filters that are available for the Camera.

You are fine with your iPhone 14 for many years and newer phones don't have the Comic filter either. The only thing you will have to consider is when your Battery Health drops below 80%, then you will need to determine if you want to spend the $99 for a battery or put that money into a newer device. Either option is fine and the choice is up to you.

Are you using a third-party messaging app?

On models that support Photographic Styles, you can edit the Photographic Style or apply a new style to photos in your library.

Note: On iPhone 16 models or later, use Photographic Styles instead of filters to give your photos a customized look. Filter effects are available on these models if you haven’t turned on Photographic Styles.