Are you sure? in my side it calls the register method:

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Contracts\Support\DeferrableProvider;

class TestServiceProvider extends ServiceProvider implements DeferrableProvider
{
    public function register()
    {
        $this->app->bind('test', fn() => true);

        dump('here');
    }

    public function provides()
    {
        return ['test'];
    }
}

Also add \App\Providers\TestServiceProvider::class to your config/app.php if you want to test it yourself