Is there a maximum number of page layouts that I can create in Application Composer?

There's no maximum number of page layouts that you can create in Application Composer for an object. As a best practice, however, avoid creating too many page layouts. This keeps your layout management tasks simpler over future releases.

For example, a good target to aim for might be 3-4 creation page layouts and 6-8 details page layouts.

Note: To avoid creating too many layouts, use the UI properties on a field itself to control things like whether or not it's visible or updatable.