Explore an option to add capabilities to a class without making it bigger

Main.php

<?php

class A {
	public static function methodA1(): string {
		return __METHOD__;
	}
}

class B {

	/**
	 * @var Main
	 */
	private $caller;

	public function __construct($caller) {
		$this->caller = $caller;
	}

	public function methodB1(): string {
		$this->caller->counter++;
		return __METHOD__;
	}
}

class Main {

	public $counter = 0;

	/**
	 * @var A
	 */
	public static $moduleA;

	/**
	 * @var B
	 */
	public $moduleB;

	/**
	 * @return A
	 */
	public static function getStaticModuleA(): A {
		self::$moduleA = new A();
		// although return A; works but phpDoc requires returning an instance
		return self::$moduleA;
	}

	/**
	 * @return B
	 */
	public function getNonStaticModuleB(): B {
		$this->moduleB = new B($this);
		return $this->moduleB;
	}

}

var_dump(Main::getStaticModuleA()::methodA1() == 'A::methodA1');

$main = new Main();

var_dump($main->getNonStaticModuleB()->methodB1() == 'B::methodB1');

var_dump($main->counter == 1);