Codeigniter 4 ajax post results in 404 error

Why there is public in your url ? 
Have you set base_url with public ?

Can you try to change 

$routes->get('filter', 'App_home::filter');

to

$routes->get('/filter', 'App_home::filter');

Should I delete public?

My baseurl is as:

Code:

public string $baseURL = 'http://localhost:80/';

I change to `$routes->get('/filter', 'App_home::filter');` but there is the same error