I strongly believe in the success of CodeIgniter 4 because it is a simple and light framework with modern architecture. For huge projects, which must be developed only by big teams, there are corporate technologies (for example, the Symfony framework). However, if your project requires the work of a few professionals, then CodeIgniter 4 is your best choice!
CodeIgniter 4 is the shortest way from your idea to its fullest implementation. The framework is very much appreciated for its flexibility. You can change your app, as your tasks change. CodeIgniter 4 is well suited to implement the concept of RAD (rapid application development).