I used to make my scripts fully DB based for configuration, When I tried to set the baseURL from the db as the default it does not work on CI4.
Hence, I'm managed now to do so by inheriting the App\Config\App by a custom ones, each one for a purpose, but I could not override the App default values by the DB ones, cause it's loaded with CodeIgniter\CodeIgniter.
I believe if there is a builtin library to merge objects preservings methods , I would use $this->config from routes to overwrite the App and load all needed settings all over with the engine.
All this is to reduce the heavy calls of config(CustomConfigFiles::class) in the baseController or any other common controller
thanks ^^