Can you achieve enlightenment or self -realization or moksha ?

The answer is no. You cannot achieve anything on the spiritual path through your ego or mind. The moment you say “I can achieve it”, the ‘I’ or ego itself is the problem here. Infact, on the other hand, to achieve these higher states of enlightenment or self- realization or moksha, your ego or ‘I’ has to die. These higher spiritual states, or for that matter any spiritual experience, can only happen through grace of god/guru/divine, and that too when you truly deserve it. You can definitely work hard to purify your inner self (your heart and mind) through sadhna/meditation and seva/selfless service, which is essential for your spiritual growth or spiritual progress, but you can never achieve anything on the spiritual path through your ego or mind. The more your inner being will be purified, the easier it will be, to surrender or drop your ego and mind, and go beyond your ego and mind. The only thing you can do on the spiritual path, is to purify your inner self, the rest will happen on its own through god/divine grace, when you are ready for it or when you deserve it. Being ready for it or deserve it means, that it is in your prarabhdha karma to receive it and it also means ,that you have purified your heart and mind enough to go beyond your ego and other impurities.